Police say they are investigating a string of robberies in Bedford Park.

They say a man has threatened random Bronx residents on the streets with either a gun or a knife four different times throughout the summer.

According to police, the suspect robbed two teenagers on July 20. They say one incident happened on East Fordham Road and the other near Jerome Avenue and East 193rd Street.

During those incidents, police say the man pulled out a gun on both victims and robbed them.

Officials say the suspect then stole from two more people on August 10. They say the robberies took place on East 181st Street and the other just two hours later near the corner of Grand Concourse and East 198th Street.

In both cases, police say he pulled out a knife and cut the chains off his victims. They say the youngest victim is a 15-year-old boy and the oldest is a 65-year-old woman.

Officials describe the suspect as a man in his early 20s, wearing his hair in either a bun or ponytail and has a tattoo on his left forearm.

They say no one was injured in all four robberies.

Anyone with information is asked to call police.