-from nydailynews.com-

By John Lauinger, Daily News Writer

An off-duty city cop out shopping busted a robber after witnessing the thug beat an elderly man with a steel pipe, police said yesterday.

New York City Police Officer Edward Bilardi, 40, of Rosedale, Queens, was food shopping Sunday afternoon when he saw a disturbing scene on the sidewalk along North Central Ave. in Valley Stream.

A thug grabbed the 76-year-old man by the throat and then bashed him in the face with a foot-long steel pipe, Nassau police said yesterday.

Immediately, the 14-year NYPD veteran raced to help the victim, police said.

“Even if he wasn’t a cop, my son would run and help anybody,” said Bilardi’s mother, Rachel Bilardi, 65, also of Rosedale. “He wouldn’t think of himself for a minute. He’s good like that.”

The victim had been strolling northbound along North Central Ave. shortly after 2p.m. when the pipe-wielding robber demanded that he empty his pockets, said Detective Lt. John Azzata, commanding officer of the Nassau 5th Detectives Squad.

After the victim coughed up the $5 he had in his pockets, the enraged robber clubbed the victim multiple times in the chest with the pipe, Azzata said.

“By the time [Bilardi] gets there, the crime has already occurred,” Azzata said.

Screaming, “Stop! I’m a police officer,” Bilardi ordered the robber to surrender - but he ran off, Azzata said. Bilardi gave chase and cornered the suspect in a nearby alleyway.

There, the desperate suspect threatened Bilardi with a shovel he had picked up, wildly swinging it in an effort to avoid the collar, Azzata said.

Meanwhile, passersby had dialed 911 upon hearing the commotion, and Nassau County Police Officer Jeffrey Rios soon joined the fray in the alleyway. Together, the two officers slapped cuffs on the suspect after a short scuffle, Azzata said.

Both officers suffered minor cuts in subduing the shovel-swinging suspect, but neither required medical attention, Azzata said. The victim was treated at a local hospital for lacerations to his chest and nose and later released, Azzata said.

The suspect, who was identified as Samuel Denis, 24, of Elmont, has prior arrests for robbery and drug possession, police said.

He was charged with first-degree robbery and resisting arrest. He was being held for observation in the psychiatric ward of Nassau University Medical Center.

Rachel Bilardi said her son, who works out of the 46th Precinct in the Bronx, was born to help others.

“He’s always been like that,” she said, pointing out that her son volunteered to help at Ground Zero after 9/11.

“He’s got a good heart. God bless him.”