New York (CNN) -- New York police Thursday were investigating a sucker-punch assault on a 23-year-old man for a possible connection to a series of attacks known as the "knockout game."
In the latest assault, the unidentified man was walking on a street in the Bronx on Wednesday afternoon when he was punched in the head and fell to the ground, police said. After he was down, two other men punched him several times before running away.
Nothing was taken from the man, and police were looking into a possible link to assaults around the country where teens randomly try to make strangers unconscious with a single blow. The victim suffered bruising and swelling to his face but refused medical treatment.
At least eight suspected "knockout" attacks have been reported since October in New York, but police have said they see no evidence of a trend.
Authorities have reported similar incidents in New York, New Jersey, Connecticut, Illinois, Missouri and Washington.
In New Haven, Connecticut, police said there were seven reported incidents possibly connected to "knockout" assaults, but it was unclear if they were carried out by the same person. There were no major injuries in the attacks, which occurred in the same three- to four-block area on November 17-18.
The assaults stopped after police questioned a suspect, though no arrest was made. "We have no reason to believe this is a hate crime," said Officer David Hartman, a New Haven police spokesman. Some previous assaults in the region have targeted Jewish people.
Hartman said police believe the attacks were copycat crimes spurred by media attention.
Youth violence expert Chuck Williams blamed the media and parents for what he called extreme aggression by America's youths. Negative attention, he said, is often rewarded.
"That's America. America loves violence, and so do our kids," he said. "We market violence to our children and we wonder why they're violent. It's because we are."
Williams, a professor of psychology and education at Drexel University in Philadelphia, said some young people are desperate for attention. He called it the "Miley Cyrus effect," where teens will do anything to get noticed, no matter how unconscionable.
"These kids know the consequences," he said. "They want to get arrested. They want to get caught, because they want that notoriety. They know they won't go away forever because they're kids. It's a win-win all around for them."