Detectives from Fawkner Embona are investigating a series of armed robberies in Craigieburn last month.
Investigators have been told a man was on the front porch of an Admiration Drive home when an unknown man walked passed about 7.15pm on 1 February.
The man walked past a few other houses before returning to the residence and threatening the 38–year-old victim with a knife.
He stole the man's phone and wallet before leaving on foot.
Detectives believe the same man may have been involved in another armed robbery later that evening.
On this occasion a 34-year-old man was walking a long Domain Way, near Bandicoot Road, about 9pm when he was confronted by a man.
The man blocked the victim's path before threatening him with a knife and stealing his phone before fleeing.
Detectives have released CCTV of a man they believe may be able to assist with their enquiries.
Anyone with information is urged to call Crime Stoppers on 1800 333 000 or log onto www.crimestoppersvic.com.au
