[UPDATE BELOW] An unidentified man has been terrorizing people and their pets in Prospect Park for the past few months, allegedly allowing his dog to attack other pets and then joining in... with an ice pick.

Witness Eric Barstad tells us that a few months ago, a friend of his was enjoying a pleasant stroll through the park when his dog was attacked by a large pit bull. Rather than trying to call his dog off, the dog's owner engaged, allegedly trapping the victim-dog between his legs and stabbing the animal nine times with what Barstad described as an ice pick.

The dog survived the stabbing, but Barstad said he knows others who have had run-ins with the Ice Pick Man, with still another friend's Doberman attacked by the same brown pit bull. This time, the man didn't use his ice pick, but he did grab the Doberman by the collar, "making it easier for the dog to attack," Barstad told us.

Barstad and his friends posted signs around the park, warning others that the man is still on the loose. Of the six victims Barstad has spoken with, at least three have filed police reports, though he believes cops have expressed little interest in tracking the man down.

Prospect Park Alliance spokesperson Paul Nelson said in an email that the NYPD and Parks Enforcement are "dealing with" the situation, since it is an "enforcement issue." The NYPD has not responded to requests for comment as to whether the suspect has been caught.

Commenters on the blog Brooklynian have had similar experiences—both with the man and his dog, and the allegedly lackluster police response. "We've run into him before his ice pick days, when he just used a cane. He's mentally off and very angry and aggressive at all times," wrote OppossumQueen. "We (myself and a friend walking our dogs on leash near the lake) had a pretty rough incident one morning and I was pretty disappointed at the police response, or lack there of."

She added that while she hasn't seen the man encouraging his dog to fight, he didn't seem to have much interest in reining it in, either.

"I've seen and had several interactions with this guy and I really think he and his dog are dangerous," she wrote. "I go very far out of my way to avoid him when I can see him, now."

Barstad has posted flyers around the park, describing the attacker as a black man in his late 20s or early 30s, standing around 5-foot-9 or 5-foot-10 with a stocky build. He tends to have a metal cane hanging from his back pocket, and wears a blue and white baseball cap. Anyone with information is asked to call Parks Enforcement Patrol at (718) 437-1350.

It should go without saying that if you see a pit bull and a man with an ice pick heading your direction—whether you're in Prospect Park, on the subway or even in your own home—run.

Update, 4:47 p.m.: Police have arrested 42-year-old Flatbush resident Donnell Barden on charges of aggravated animal cruelty, menacing and criminal possession of a weapon.

According to a police spokesperson, the arrest was made on the basis of a complaint filed on May 17, in which Barden allegedly stabbed a dog that was fighting with his dog, also allegedly hitting the dog's owner after he tried to separate them.

The spokesperson added that anyone else who has been attacked by Barden should alert police immediately.