A 15-year-old boy punched an 82-year-old man and stole the chain off his neck — before being chased down by a detective who witnessed the attack, police said.

15-Year-Old Assaults 82-Year-Old; Steals Jewelry

A 15-year-old boy punched an 82-year-old man and stole the chain off his neck — before being chased down by a detective who witnessed the attack, police said.

The victim was walking on the corner of Schenectady and East New York avenues at 4:50 p.m. on June 19, when the teen ran up to him, punched him in the face and ripped the chain from his neck, police said.

An NYPD detective who saw the incident chased the thief and arrested him, authorities said.

The 82-year-old was treated for minor injuries at Kingsbrook Jewish Medical Center and released, police said.

Click here to continue reading at DNAinfo.