diff --git a/include/input/InputVerifier.h b/include/input/InputVerifier.h
index b857482..14dd463 100644
--- a/include/input/InputVerifier.h
+++ b/include/input/InputVerifier.h
@@ -46,7 +46,7 @@
 public:
     InputVerifier(const std::string& name);
 
-    android::base::Result<void> processMovement(int32_t deviceId, int32_t action,
+    android::base::Result<void> processMovement(int32_t deviceId, int32_t source, int32_t action,
                                                 uint32_t pointerCount,
                                                 const PointerProperties* pointerProperties,
                                                 const PointerCoords* pointerCoords, int32_t flags);
diff --git a/libs/input/Android.bp b/libs/input/Android.bp
index 36a01d3..ab4af1a 100644
--- a/libs/input/Android.bp
+++ b/libs/input/Android.bp
@@ -90,6 +90,28 @@
         "--allowlist-var=AMOTION_EVENT_ACTION_DOWN",
         "--allowlist-var=AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT",
         "--allowlist-var=MAX_POINTER_ID",
+        "--allowlist-var=AINPUT_SOURCE_CLASS_NONE",
+        "--allowlist-var=AINPUT_SOURCE_CLASS_BUTTON",
+        "--allowlist-var=AINPUT_SOURCE_CLASS_POINTER",
+        "--allowlist-var=AINPUT_SOURCE_CLASS_NAVIGATION",
+        "--allowlist-var=AINPUT_SOURCE_CLASS_POSITION",
+        "--allowlist-var=AINPUT_SOURCE_CLASS_JOYSTICK",
+        "--allowlist-var=AINPUT_SOURCE_UNKNOWN",
+        "--allowlist-var=AINPUT_SOURCE_KEYBOARD",
+        "--allowlist-var=AINPUT_SOURCE_DPAD",
+        "--allowlist-var=AINPUT_SOURCE_GAMEPAD",
+        "--allowlist-var=AINPUT_SOURCE_TOUCHSCREEN",
+        "--allowlist-var=AINPUT_SOURCE_MOUSE",
+        "--allowlist-var=AINPUT_SOURCE_STYLUS",
+        "--allowlist-var=AINPUT_SOURCE_BLUETOOTH_STYLUS",
+        "--allowlist-var=AINPUT_SOURCE_TRACKBALL",
+        "--allowlist-var=AINPUT_SOURCE_MOUSE_RELATIVE",
+        "--allowlist-var=AINPUT_SOURCE_TOUCHPAD",
+        "--allowlist-var=AINPUT_SOURCE_TOUCH_NAVIGATION",
+        "--allowlist-var=AINPUT_SOURCE_JOYSTICK",
+        "--allowlist-var=AINPUT_SOURCE_HDMI",
+        "--allowlist-var=AINPUT_SOURCE_SENSOR",
+        "--allowlist-var=AINPUT_SOURCE_ROTARY_ENCODER",
     ],
 
     static_libs: [
diff --git a/libs/input/InputTransport.cpp b/libs/input/InputTransport.cpp
index 1600013..b5a823d 100644
--- a/libs/input/InputTransport.cpp
+++ b/libs/input/InputTransport.cpp
@@ -632,8 +632,8 @@
                                 MotionEvent::actionToString(action).c_str()));
     if (verifyEvents()) {
         Result<void> result =
-                mInputVerifier.processMovement(deviceId, action, pointerCount, pointerProperties,
-                                               pointerCoords, flags);
+                mInputVerifier.processMovement(deviceId, source, action, pointerCount,
+                                               pointerProperties, pointerCoords, flags);
         if (!result.ok()) {
             LOG(FATAL) << "Bad stream: " << result.error();
         }
diff --git a/libs/input/InputVerifier.cpp b/libs/input/InputVerifier.cpp
index 6c602e0..cec2445 100644
--- a/libs/input/InputVerifier.cpp
+++ b/libs/input/InputVerifier.cpp
@@ -33,7 +33,7 @@
 InputVerifier::InputVerifier(const std::string& name)
       : mVerifier(android::input::verifier::create(rust::String::lossy(name))){};
 
-Result<void> InputVerifier::processMovement(DeviceId deviceId, int32_t action,
+Result<void> InputVerifier::processMovement(DeviceId deviceId, int32_t source, int32_t action,
                                             uint32_t pointerCount,
                                             const PointerProperties* pointerProperties,
                                             const PointerCoords* pointerCoords, int32_t flags) {
@@ -43,8 +43,8 @@
     }
     rust::Slice<const RustPointerProperties> properties{rpp.data(), rpp.size()};
     rust::String errorMessage =
-            android::input::verifier::process_movement(*mVerifier, deviceId, action, properties,
-                                                       static_cast<uint32_t>(flags));
+            android::input::verifier::process_movement(*mVerifier, deviceId, source, action,
+                                                       properties, static_cast<uint32_t>(flags));
     if (errorMessage.empty()) {
         return {};
     } else {
diff --git a/libs/input/rust/input.rs b/libs/input/rust/input.rs
index 9d3b386..9725b00 100644
--- a/libs/input/rust/input.rs
+++ b/libs/input/rust/input.rs
@@ -23,6 +23,54 @@
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub struct DeviceId(pub i32);
 
+#[repr(u32)]
+pub enum SourceClass {
+    None = input_bindgen::AINPUT_SOURCE_CLASS_NONE,
+    Button = input_bindgen::AINPUT_SOURCE_CLASS_BUTTON,
+    Pointer = input_bindgen::AINPUT_SOURCE_CLASS_POINTER,
+    Navigation = input_bindgen::AINPUT_SOURCE_CLASS_NAVIGATION,
+    Position = input_bindgen::AINPUT_SOURCE_CLASS_POSITION,
+    Joystick = input_bindgen::AINPUT_SOURCE_CLASS_JOYSTICK,
+}
+
+bitflags! {
+    /// Source of the input device or input events.
+    pub struct Source: u32 {
+        /// SOURCE_UNKNOWN
+        const Unknown = input_bindgen::AINPUT_SOURCE_UNKNOWN;
+        /// SOURCE_KEYBOARD
+        const Keyboard = input_bindgen::AINPUT_SOURCE_KEYBOARD;
+        /// SOURCE_DPAD
+        const Dpad = input_bindgen::AINPUT_SOURCE_DPAD;
+        /// SOURCE_GAMEPAD
+        const Gamepad = input_bindgen::AINPUT_SOURCE_GAMEPAD;
+        /// SOURCE_TOUCHSCREEN
+        const Touchscreen = input_bindgen::AINPUT_SOURCE_TOUCHSCREEN;
+        /// SOURCE_MOUSE
+        const Mouse = input_bindgen::AINPUT_SOURCE_MOUSE;
+        /// SOURCE_STYLUS
+        const Stylus = input_bindgen::AINPUT_SOURCE_STYLUS;
+        /// SOURCE_BLUETOOTH_STYLUS
+        const BluetoothStylus = input_bindgen::AINPUT_SOURCE_BLUETOOTH_STYLUS;
+        /// SOURCE_TRACKBALL
+        const Trackball = input_bindgen::AINPUT_SOURCE_TRACKBALL;
+        /// SOURCE_MOUSE_RELATIVE
+        const MouseRelative = input_bindgen::AINPUT_SOURCE_MOUSE_RELATIVE;
+        /// SOURCE_TOUCHPAD
+        const Touchpad = input_bindgen::AINPUT_SOURCE_TOUCHPAD;
+        /// SOURCE_TOUCH_NAVIGATION
+        const TouchNavigation = input_bindgen::AINPUT_SOURCE_TOUCH_NAVIGATION;
+        /// SOURCE_JOYSTICK
+        const Joystick = input_bindgen::AINPUT_SOURCE_JOYSTICK;
+        /// SOURCE_HDMI
+        const HDMI = input_bindgen::AINPUT_SOURCE_HDMI;
+        /// SOURCE_SENSOR
+        const Sensor = input_bindgen::AINPUT_SOURCE_SENSOR;
+        /// SOURCE_ROTARY_ENCODER
+        const RotaryEncoder = input_bindgen::AINPUT_SOURCE_ROTARY_ENCODER;
+    }
+}
+
 /// A rust enum representation of a MotionEvent action.
 #[repr(u32)]
 pub enum MotionAction {
@@ -134,3 +182,11 @@
         const NO_FOCUS_CHANGE = input_bindgen::AMOTION_EVENT_FLAG_NO_FOCUS_CHANGE;
     }
 }
+
+impl Source {
+    /// Return true if this source is from the provided class
+    pub fn is_from_class(&self, source_class: SourceClass) -> bool {
+        let class_bits = source_class as u32;
+        self.bits() & class_bits == class_bits
+    }
+}
diff --git a/libs/input/rust/input_verifier.rs b/libs/input/rust/input_verifier.rs
index 64c0466..2d94e70 100644
--- a/libs/input/rust/input_verifier.rs
+++ b/libs/input/rust/input_verifier.rs
@@ -17,7 +17,7 @@
 //! Contains the InputVerifier, used to validate a stream of input events.
 
 use crate::ffi::RustPointerProperties;
-use crate::input::{DeviceId, MotionAction, MotionFlags};
+use crate::input::{DeviceId, MotionAction, MotionFlags, Source, SourceClass};
 use log::info;
 use std::collections::HashMap;
 use std::collections::HashSet;
@@ -51,10 +51,15 @@
     pub fn process_movement(
         &mut self,
         device_id: DeviceId,
+        source: Source,
         action: u32,
         pointer_properties: &[RustPointerProperties],
         flags: MotionFlags,
     ) -> Result<(), String> {
+        if !source.is_from_class(SourceClass::Pointer) {
+            // Skip non-pointer sources like MOUSE_RELATIVE for now
+            return Ok(());
+        }
         if self.should_log {
             info!(
                 "Processing {} for device {:?} ({} pointer{}) on {}",
@@ -68,6 +73,13 @@
 
         match action.into() {
             MotionAction::Down => {
+                if pointer_properties.len() != 1 {
+                    return Err(format!(
+                        "{}: Invalid DOWN event: there are {} pointers in the event",
+                        self.name,
+                        pointer_properties.len()
+                    ));
+                }
                 let it = self
                     .touching_pointer_ids_by_device
                     .entry(device_id)
@@ -90,10 +102,19 @@
                     ));
                 }
                 let it = self.touching_pointer_ids_by_device.get_mut(&device_id).unwrap();
+                if it.len() != pointer_properties.len() - 1 {
+                    return Err(format!(
+                        "{}: There are currently {} touching pointers, but the incoming \
+                         POINTER_DOWN event has {}",
+                        self.name,
+                        it.len(),
+                        pointer_properties.len()
+                    ));
+                }
                 let pointer_id = pointer_properties[action_index].id;
                 if it.contains(&pointer_id) {
                     return Err(format!(
-                        "{}: Pointer with id={} not found in the properties",
+                        "{}: Pointer with id={} already present found in the properties",
                         self.name, pointer_id
                     ));
                 }
@@ -108,11 +129,10 @@
                 }
             }
             MotionAction::PointerUp { action_index } => {
-                if !self.touching_pointer_ids_by_device.contains_key(&device_id) {
+                if !self.ensure_touching_pointers_match(device_id, pointer_properties) {
                     return Err(format!(
-                        "{}: Received POINTER_UP but no pointers are currently down for device \
-                        {:?}",
-                        self.name, device_id
+                        "{}: ACTION_POINTER_UP touching pointers don't match",
+                        self.name
                     ));
                 }
                 let it = self.touching_pointer_ids_by_device.get_mut(&device_id).unwrap();
@@ -120,6 +140,13 @@
                 it.remove(&pointer_id);
             }
             MotionAction::Up => {
+                if pointer_properties.len() != 1 {
+                    return Err(format!(
+                        "{}: Invalid UP event: there are {} pointers in the event",
+                        self.name,
+                        pointer_properties.len()
+                    ));
+                }
                 if !self.touching_pointer_ids_by_device.contains_key(&device_id) {
                     return Err(format!(
                         "{} Received ACTION_UP but no pointers are currently down for device {:?}",
@@ -246,6 +273,7 @@
     use crate::DeviceId;
     use crate::MotionFlags;
     use crate::RustPointerProperties;
+    use crate::Source;
     #[test]
     fn single_pointer_stream() {
         let mut verifier = InputVerifier::new("Test", /*should_log*/ false);
@@ -253,6 +281,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_DOWN,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -261,6 +290,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_MOVE,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -269,6 +299,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_UP,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -283,6 +314,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_DOWN,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -291,6 +323,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_MOVE,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -299,6 +332,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(2),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_DOWN,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -307,6 +341,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(2),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_MOVE,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -315,6 +350,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_UP,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -329,6 +365,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_DOWN,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -337,6 +374,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_CANCEL,
                 &pointer_properties,
                 MotionFlags::CANCELED,
@@ -351,6 +389,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_DOWN,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -359,6 +398,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_CANCEL,
                 &pointer_properties,
                 MotionFlags::empty(), // forgot to set FLAG_CANCELED
@@ -373,6 +413,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_UP,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -387,6 +428,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_HOVER_ENTER,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -396,6 +438,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_HOVER_MOVE,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -405,6 +448,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_HOVER_EXIT,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -414,6 +458,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_HOVER_ENTER,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -428,6 +473,7 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_HOVER_ENTER,
                 &pointer_properties,
                 MotionFlags::empty(),
@@ -437,10 +483,28 @@
         assert!(verifier
             .process_movement(
                 DeviceId(1),
+                Source::Touchscreen,
                 input_bindgen::AMOTION_EVENT_ACTION_HOVER_ENTER,
                 &pointer_properties,
                 MotionFlags::empty(),
             )
             .is_err());
     }
+
+    // Send a MOVE without a preceding DOWN event. This is OK because it's from source
+    // MOUSE_RELATIVE, which is used during pointer capture. The verifier should allow such event.
+    #[test]
+    fn relative_mouse_move() {
+        let mut verifier = InputVerifier::new("Test", /*should_log*/ false);
+        let pointer_properties = Vec::from([RustPointerProperties { id: 0 }]);
+        assert!(verifier
+            .process_movement(
+                DeviceId(2),
+                Source::MouseRelative,
+                input_bindgen::AMOTION_EVENT_ACTION_MOVE,
+                &pointer_properties,
+                MotionFlags::empty(),
+            )
+            .is_ok());
+    }
 }
diff --git a/libs/input/rust/lib.rs b/libs/input/rust/lib.rs
index 1d3c434..01d9599 100644
--- a/libs/input/rust/lib.rs
+++ b/libs/input/rust/lib.rs
@@ -19,7 +19,7 @@
 mod input;
 mod input_verifier;
 
-pub use input::{DeviceId, MotionAction, MotionFlags};
+pub use input::{DeviceId, MotionAction, MotionFlags, Source};
 pub use input_verifier::InputVerifier;
 
 #[cxx::bridge(namespace = "android::input")]
@@ -51,6 +51,7 @@
         fn process_movement(
             verifier: &mut InputVerifier,
             device_id: i32,
+            source: u32,
             action: u32,
             pointer_properties: &[RustPointerProperties],
             flags: u32,
@@ -73,12 +74,14 @@
 fn process_movement(
     verifier: &mut InputVerifier,
     device_id: i32,
+    source: u32,
     action: u32,
     pointer_properties: &[RustPointerProperties],
     flags: u32,
 ) -> String {
     let result = verifier.process_movement(
         DeviceId(device_id),
+        Source::from_bits(source).unwrap(),
         action,
         pointer_properties,
         MotionFlags::from_bits(flags).unwrap(),
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index 9cd1e09..4657c01 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -4324,9 +4324,9 @@
                 mVerifiersByDisplay.try_emplace(args.displayId,
                                                 StringPrintf("display %" PRId32, args.displayId));
         Result<void> result =
-                it->second.processMovement(args.deviceId, args.action, args.getPointerCount(),
-                                           args.pointerProperties.data(), args.pointerCoords.data(),
-                                           args.flags);
+                it->second.processMovement(args.deviceId, args.source, args.action,
+                                           args.getPointerCount(), args.pointerProperties.data(),
+                                           args.pointerCoords.data(), args.flags);
         if (!result.ok()) {
             LOG(FATAL) << "Bad stream: " << result.error() << " caused by " << args.dump();
         }