They say he robbed the same convenience store twice.
Surveillance video from last week shows the suspect dragging a customer by the neck before pointing a handgun at the pregnant clerk and demanding money.
He fled on foot with a large sum of cash.
There was a similar robbery in November - and it involved the same clerk. In that case, the suspect got away in a white, 1990s Chevy Suburban.
Anyone who recognizes the suspect or has more information is asked to call the Palmdale sheriff's station at (661)2727-2400 or Crime Stoppers at (800)222-8477.