D.C. police are looking for a man who knocked a 63-year-old man out with one punch in an apparent robbery May 17 in Southeast.

About 5:45 p.m. that Sunday, a man in a red shirt exchanged words with the victim in the 2900 block of Martin Luther King Jr. Avenue SE.

WARNING: Some may find the surveillance video below disturbing.

Surveillance video from nearby Petey Greene Community Center shows the man in a red shirt punch the 63-year-old victim, dropping him to the ground. He stepped away from the motionless victim before returning, bending over him, and apparently going through his pockets and taking a dollar.

Several other people seen in the video did nothing to intervene or assist the victim.

Anyone with information about the case should call police at 202-727-9099 or by texting the tip to 50411.