Intruder Catcher

Catch anyone who tries to snoop on your phone.

Intruder Catcher silently captures a photo with your front camera the moment someone enters the wrong PIN, pattern, or password on your lock screen. The intruder sees nothing on the screen — no preview, no shutter sound, no flash — but a crisp photo, the exact timestamp, the GPS location, and a short audio clip are saved privately on your device for you to review later.

KEY FEATURES

• Silent front-camera capture on every wrong unlock attempt

• Configurable trigger threshold (1 to 5 wrong attempts before a photo is taken)

• Optional GPS location stamp on every capture — tap to open it in Google Maps

• Optional 3-second ambient audio recording with each photo

• Built-in gallery showing every capture with timestamp

• Detail screen with metadata: time, location, battery level, attempt count, audio playback

• One-tap share or delete of any capture

• Master switch to pause the watcher without removing Device Admin

• Modern Material 3 design built with Jetpack Compose

• Works 24×7 — once enabled, the app survives reboots without any persistent service draining your battery

PRIVACY FIRST

Your captures never leave your phone. Everything — photos, audio, location, metadata — is stored in app-private storage that no other app can read. We do not have a server, we do not have an account system, we do not collect, transmit, or sell any of your data. The app is fully functional with absolutely no internet connection required.

HOW IT WORKS

Intruder Catcher uses Android's official Device Administrator API to be notified by the operating system whenever a wrong unlock code is entered. This is the only legitimate way for an Android app to detect failed unlock attempts. We only request the "Watch login attempts" capability — the app cannot wipe your phone, change your password, lock you out, or do anything else with admin privileges. You can revoke Device Admin at any time from Android Settings.

When a wrong attempt is detected and your configured threshold is reached, a short-lived foreground service spins up, takes the photo silently in the background, optionally records audio and a GPS fix, saves everything to private local storage, and shuts itself down. The whole pipeline takes a couple of seconds and uses minimal battery.

WHAT YOU NEED TO ENABLE

After installing, the Home screen walks you through three quick setup steps:

1. Enable Device Admin (system Settings opens — confirm and come back)

2. Grant Camera, Microphone, Location, and Notifications permissions

3. Whitelist the app from battery optimisations so Android does not suspend captures while the screen is off

A persistent notification briefly appears whenever a capture happens — Android requires this for any app that uses the camera from the background and we cannot legally hide it. Likewise, Android 12 and newer show the green camera/microphone indicator in the status bar whenever the camera fires. These are operating-system-level transparency features that protect users; they are not optional.

PERFECT FOR

• Catching the family member who keeps secretly checking your phone

• Identifying anyone who tries to unlock your phone at the office, gym, or classroom

• Recovering evidence if your phone is stolen and the thief guesses the PIN

• Quietly logging every failed unlock attempt

REQUIREMENTS: Android 12 (API 31) or newer, a front-facing camera, and lock-screen security enabled.

This app does not bypass your lock screen or recover passwords. It only photographs whoever tries to unlock your device after a failure, and is intended for use on your own phone by its legitimate owner. Photographing people without their knowledge may be regulated where you live — check your local laws before relying on captures as formal evidence.