Police arrested three men and are looking for a fourth after an armed robbery at a medical marijuana dispensary in Hamilton's downtown.

Two of the suspects, a 21-year-old man and 17-year-old youth, were previously involved in another armed robbery at a dispensary in the east end earlier this month, police said.

The latest incident happened Tuesday around 11:30 p.m. Police say four suspects, armed with a firearm, entered the Delta Nine Medical Dispensary on James Street North. 

They got away before police got there but citizens pointed them in the direction they'd fled, and police with the canine unit tracked down three of the suspects.

Police are still looking for one man.

They're not saying what was taken from the dispensary.

A second 17-year-old youth was also arrested Tuesday.