New York ? A homeless man was arrested Wednesday in the stabbing of four people, including three tourists, who were attacked in a 12-hour span in Manhattan.

Investigators were questioning the 21-year-old man but did not have a motive.

Two of the four victims were stabbed near a Times Square hotel; the others were attacked inside the subway system. Three were hospitalized, and police said they were expected to survive.

Police spokesman Paul Browne said the suspect admitted stabbing two Canadians, a Mexican immigrant and a young man from Texas.

Police Commissioner Ray Kelly said there was no evidence to suggest the man was targeting tourists. He said investigators recovered the folding knife used in at least two of the attacks when they arrested the suspect.

Charges were pending against Kenny Alexis, who had been living in a shelter.