THE BRONX - Police have identified the teenager they believe is behind a string of robberies in Morris Heights.

Investigators released surveillance video that allegedly shows 19-year-old Bryan Rivas, who they say robbed four people over the course of one week between Aug. 30 and Sept. 4.

In the first three attacks, cops say Rivas punched or shoved his victims before robbing them, but escalated to flashing a gun in the most recent incident.

Rivas is described as being about 5 feet 11 inches tall and 180 pounds. Anyone with information is urged to contact police.