A man beat a fellow subway rider in New York in February.
The victim was knocked out by the apparently unprovoked attack.
He was treated at the scene by paramedics.
He sustained injuries of swelling to his face and two chipped teeth.
The police identified the suspect as 24-year-old Jose Hasing of Queens on March 7.
Hasing has previously been arrested 15 times.
Police said they do not know what led the suspect to attack the other man.
Police are asking anyone with information on Hasing's whereabouts to come forward.
Credit: New York Police Department via Reuters