A Manhattan chef visiting Philadelphia was brutally beaten Tuesday night in an unprovoked attack that appears to fit the pattern of the "knockout game" assaults, CBS 3 reports. Diego Moya, 30, was walking along Market Street between 2nd and 3rd just after 11 p.m. when he was assaulted by a group of six to eight males, ages 16 to 21. They broke his jaw and nose, and fled without robbing him.

Moya's jaw is wired shut and will remain so for the next four weeks as he recovers. "Ate dinner with friends and on my way back to hostel got pizza as I walked down the alley I was hit from behind," Moya wrote in an email to the Daily News. "Nothing was stolen from me which leads me to believe this was that ‘game.’ I hope I'm the last person this happens to. I'm not well, a lot of swelling and overall pain. Should be four weeks until I lose the wires and can eat normally, which is devastating being a chef. Means I can't work."

Moya says police "mentioned [the knockout game] as a possibility." The assault happened a day after Philadelphia mayor Michael Nutter and Police Commissioner Charles Ramsey held a press conference to warn residents and potential perpetrators of the knockout game, which involves sucker-punching a passerby in an attempt to knock him or her unconscious.

"This is not a game," Nutter said at the press conference. "You can seriously injure or possibly kill someone. Your child’s life will be dramatically changed, and probably yours as well as a parent. So let’s cut out the nonsense. There are many other things that people can do to enjoy themselves. This is not one of them... There’s no excuse for this kind of behavior, it will not be tolerated here in the city. We will do everything we can to both prevent, but if someone does engage, we will catch you. You’ll be prosecuted, and your life will be changed dramatically."

Last Friday Philadelphia police arrested a 15-year-old in connection with a “knockout” attack outside a pizza parlor. "Someone asked me for a cigarette and by the time I got my hands out my pocket, I was getting hit by four kids,” victim Mark Cumberland told CBS, adding that he now has trouble seeing, breathing, and swallowing. "There’s no reason at all. I mean, I didn’t get robbed, they didn’t take nothing from me. They just beat me up."

At a press conference last week, NYPD Commissioner Ray Kelly confirmed there have been seven similar attacks—namely, in which a victim is beaten over the head by one or more assailants without provocation—in Crown Heights, as well as one in Borough Park, though police have not concluded that the assaults were definitively part of a "knockout" game. Earlier this month Amrit Marajh, 28, was charged with aggravated harassment in the second degree as a hate crime, third-degree assault, and third-degree assault in connection to an attack on a Jewish man in Borough Park.