NEW YORK (CBSNewYork) — Police late Friday were on the hunt for suspects on bikes who have been robbing people at random in Riverside Park.

As CBS2’s Brian Conybeare reported, the suspects have struck at least seven times in just the last month.

Riverside Park is a beautiful four-mile stretch of Hudson River waterfront from 72nd Street to 158th Street. It is popular with cyclists, joggers and families.

But on Aug. 15, the peaceful setting turned terrifying when four teens on bikes tried to rob a man who as of Friday was still too frightened to show his face.

“One of them passed me and blocked the way,” the man said.

The 65-year-old from the Upper East Side said the group surrounded him on a narrow stretch of the bike path south of 125th Street trying to steal his bicycle, but he refused.

“This older guy had a knife,” the man said. “They approached me and started beating me; punching me in the face.”

The man said he was punched six or seven times suffering a black eye. But then strangers intervened.

“Fortunately for me, two other cyclists showed up – like a man and a woman — and my understanding, these two people scared them away,” the man said.

Police sources confirm there were seven similar attacks in Riverside Park between the end of July and Aug. 15 — all involving a roving pack of teens on bikes.

It is a disturbing trend for park goers.

“It’s a little scary to think about,” said parkgoer Lorna Begg.

“I’m definitely surprised,” said parkgoer Brandon Gleason. “I still don’t think twice, and only because there’s so many people right here. Maybe if it’s in a closed off area that’s a little more secluded, I’d probably be looking behind my shoulder.”

New York City Park Advocates President Geoffrey Croft said parks are supposed to be safe havens. But in fact, he said, Riverside Park had the third most crimes out of the more than 1,500 parks citywide last year.

“The public expects to be safe, but what we’re seeing time and time again is that’s not happening,” Croft said.

The muggings are happening both during the day and after dark. The suspect has gotten away mostly with cash and cellphones, police said.

A spokesman for Mayor Bill de Blasio said crime in city parks is relatively rare. But police have stepped up patrols in Riverside Park and hope to catch the suspects before anyone else is attacked.

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