diff --git a/tools/edit_monitor/daemon_manager.py b/tools/edit_monitor/daemon_manager.py
index 0c31ab8..a352e30 100644
--- a/tools/edit_monitor/daemon_manager.py
+++ b/tools/edit_monitor/daemon_manager.py
@@ -149,15 +149,15 @@
             edit_event_pb2.EditEvent.KILLED_DUE_TO_EXCEEDED_MEMORY_USAGE
         )
         logging.error(
-            "Daemon process is consuming too much memory, rebooting...")
+            "Daemon process is consuming too much memory, rebooting..."
+        )
         self.reboot()
 
       if self.max_cpu_usage >= cpu_threshold:
         self._send_error_event_to_clearcut(
             edit_event_pb2.EditEvent.KILLED_DUE_TO_EXCEEDED_CPU_USAGE
         )
-        logging.error(
-            "Daemon process is consuming too much cpu, killing...")
+        logging.error("Daemon process is consuming too much cpu, killing...")
         self._terminate_process(self.daemon_process.pid)
 
     logging.info(
@@ -179,7 +179,7 @@
         self._wait_for_process_terminate(self.daemon_process.pid, 1)
         if self.daemon_process.is_alive():
           self._terminate_process(self.daemon_process.pid)
-      self._remove_pidfile()
+      self._remove_pidfile(self.pid)
       logging.info("Successfully stopped daemon manager.")
     except Exception as e:
       logging.exception("Failed to stop daemon manager with error %s", e)
@@ -253,11 +253,15 @@
     if ex_pid:
       logging.info("Found another instance with pid %d.", ex_pid)
       self._terminate_process(ex_pid)
-      self._remove_pidfile()
+      self._remove_pidfile(ex_pid)
 
-  def _read_pid_from_pidfile(self):
-    with open(self.pid_file_path, "r") as f:
-      return int(f.read().strip())
+  def _read_pid_from_pidfile(self) -> int | None:
+    try:
+      with open(self.pid_file_path, "r") as f:
+        return int(f.read().strip())
+    except FileNotFoundError as e:
+      logging.warning("pidfile %s does not exist.", self.pid_file_path)
+      return None
 
   def _write_pid_to_pidfile(self):
     """Creates a pidfile and writes the current pid to the file.
@@ -333,7 +337,23 @@
       )
       return True
 
-  def _remove_pidfile(self):
+  def _remove_pidfile(self, expected_pid: int):
+    recorded_pid = self._read_pid_from_pidfile()
+
+    if recorded_pid is None:
+      logging.info("pid file %s already removed.", self.pid_file_path)
+      return
+
+    if recorded_pid != expected_pid:
+      logging.warning(
+          "pid file contains pid from a different process, expected pid: %d,"
+          " actual pid: %d.",
+          expected_pid,
+          recorded_pid,
+      )
+      return
+
+    logging.debug("removing pidfile written by process %s", expected_pid)
     try:
       os.remove(self.pid_file_path)
     except FileNotFoundError:
@@ -378,9 +398,7 @@
       uptime_end = float(f.readline().split()[0])
 
     return (
-        (total_end_time - total_start_time)
-        / (uptime_end - uptime_start)
-        * 100
+        (total_end_time - total_start_time) / (uptime_end - uptime_start) * 100
     )
 
   def _get_total_cpu_time(self, pid: int) -> float:
diff --git a/tools/edit_monitor/edit_monitor_integration_test.py b/tools/edit_monitor/edit_monitor_integration_test.py
index 3d28274..f39b936 100644
--- a/tools/edit_monitor/edit_monitor_integration_test.py
+++ b/tools/edit_monitor/edit_monitor_integration_test.py
@@ -15,6 +15,7 @@
 """Integration tests for Edit Monitor."""
 
 import glob
+from importlib import resources
 import logging
 import os
 import pathlib
@@ -25,8 +26,6 @@
 import tempfile
 import time
 import unittest
-
-from importlib import resources
 from unittest import mock
 
 
@@ -49,7 +48,8 @@
     self.root_monitoring_path.mkdir()
     self.edit_monitor_binary_path = self._import_executable("edit_monitor")
     self.patch = mock.patch.dict(
-        os.environ, {'ENABLE_ANDROID_EDIT_MONITOR': 'true'})
+        os.environ, {"ENABLE_ANDROID_EDIT_MONITOR": "true"}
+    )
     self.patch.start()
 
   def tearDown(self):
@@ -83,7 +83,21 @@
 
     self.assertEqual(self._get_logged_events_num(), 4)
 
-  def _start_edit_monitor_process(self):
+  def test_start_multiple_edit_monitor_only_one_started(self):
+    p1 = self._start_edit_monitor_process(wait_for_observer_start=False)
+    p2 = self._start_edit_monitor_process(wait_for_observer_start=False)
+    p3 = self._start_edit_monitor_process(wait_for_observer_start=False)
+
+    live_processes = self._get_live_processes([p1, p2, p3])
+
+    # Cleanup all live processes.
+    for p in live_processes:
+      os.kill(p.pid, signal.SIGINT)
+      p.communicate()
+
+    self.assertEqual(len(live_processes), 1)
+
+  def _start_edit_monitor_process(self, wait_for_observer_start=True):
     command = f"""
     export TMPDIR="{self.working_dir.name}"
     {self.edit_monitor_binary_path} --path={self.root_monitoring_path} --dry_run"""
@@ -94,7 +108,9 @@
         start_new_session=True,
         executable="/bin/bash",
     )
-    self._wait_for_observer_start(time_out=5)
+    if wait_for_observer_start:
+      self._wait_for_observer_start(time_out=5)
+
     return p
 
   def _wait_for_observer_start(self, time_out):
@@ -125,6 +141,18 @@
 
     return 0
 
+  def _get_live_processes(self, processes):
+    live_processes = []
+    for p in processes:
+      try:
+        p.wait(timeout=5)
+      except subprocess.TimeoutExpired as e:
+        live_processes.append(p)
+        logging.info("process: %d still alive.", p.pid)
+      else:
+        logging.info("process: %d stopped.", p.pid)
+    return live_processes
+
   def _import_executable(self, executable_name: str) -> pathlib.Path:
     binary_dir = pathlib.Path(self.working_dir.name).joinpath("binary")
     binary_dir.mkdir()
diff --git a/tools/edit_monitor/main.py b/tools/edit_monitor/main.py
index 49385f1..7ca0daa 100644
--- a/tools/edit_monitor/main.py
+++ b/tools/edit_monitor/main.py
@@ -72,7 +72,8 @@
   root_logging_dir = tempfile.mkdtemp(prefix='edit_monitor_')
   _, log_path = tempfile.mkstemp(dir=root_logging_dir, suffix='.log')
 
-  log_fmt = '%(asctime)s %(filename)s:%(lineno)s:%(levelname)s: %(message)s'
+
+  log_fmt = '%(asctime)s.%(msecs)03d %(filename)s:%(lineno)s:%(levelname)s: %(message)s'
   date_fmt = '%Y-%m-%d %H:%M:%S'
   log_level = logging.DEBUG if verbose else logging.INFO