Police released a photo Wednesday afternoon of a man wanted for first-degree murder in a fatal stabbing that happened outside of the victim’s home Monday night.

George Gatsiopoulos, 57, was killed at 44 S. Pennsylvania Street, according to Denver Police.

Donald Montoya has been identified as a suspect in his death, but his whereabouts aren’t known.

Anonymous tips can be submitted by calling Metro Denver Crime Stoppers at 720-913-STOP (7867) or by using the Metro Denver Crime Stoppers mobile app. All tipsters remain anonymous and are eligible for an award of up to $2,000.

The Metro Denver Crime Stoppers mobile app is immediately available as a free download on the App Store for Apple devices, on Google Play for Android devices and on the BlackBerry App World for select BlackBerry devices. To learn more about Crime Stoppers visit the website at http://metrodenvercrimestoppers.com/.