By David Spunt

PHILADELPHIA (CBS)—Philadelphia Police detectives are looking for a man who they say stalked, beat and robbed an elderly couple in West Philadelphia.

Authorities say it happened around 2:30 p.m. on Wednesday, April 19 near 61st and Market Street.

William Ravenell, 86, was walking home after stopping to buy food and lottery tickets in West Philadelphia. Police say a man is seen in surveillance video following the Korean War veteran. Off camera, police say the suspect harassed Ravenell with a razor blade and asked him for money. Police say Ravenell ignored the suspect and started walking home.

Authorities say the suspect followed Ravenell, and forced his way into the home. He then attacked the 86-year-old, by punching him and stealing his lottery tickets, according to detectives.

“He pushed me down on the couch and started punching,” Ravenell told CBS3.

Authorities say his wife, who is 83, ran into the living room to help, but the suspect attacked her as well by choking her.

Authorities say the suspect got away with $50-$60 in lottery tickets.

“It’s just horrible to see this occur. It’s frustrating for law enforcement officers to have this person walking the streets,” Lt. John Walker with the Philadelphia Police Department told Eyewitness News.

The suspect is described as a black man, wearing dark colored zip-up hooded sweatshirt with a lime green t-shirt underneath, a dark colored knit hat and dark colored jeans.

Anyone with any information is asked to call police at 215.686.TIPS.