Detectives were searching on Wednesday for a 25-year-old man in connection with a series of attacks on Asian women in Manhattan over the last week.

Relatives of the man, who was identified by friends and associates as Tyrelle D. Shaw, contacted the police after seeing surveillance video released after the most recent attack on Monday, according to a law enforcement official who spoke on the condition of anonymity because the investigation was continuing.

Mr. Shaw’s friends and relatives became increasingly concerned after a post appeared on his blog describing his infatuation with Asian women, claiming a connection to the crimes and outlining his intention to end his life.

“I never wanted to reach the conclusion that Asian women would never take me serious, because of the color of my skin,” read the post attributed to Mr. Shaw, who is black. “Inform N.Y.P.D. they could stop searching for me because I’m going to commit suicide.”