Philadelphia police are looking for suspects in three early-morning Saturday stabbings, each of which put a man in the hospital.

At 4 a.m., police rolled up to 17th and Walnut Streets in Center City responding to a report of an assault victim. They found a 31-year-old man, cut in the lower abdomen, who told them he had been stabbed four blocks east, at 13th and Walnut. With officers on the scene, he "became unresponsive" and was taken to Hahnemann Hospital, where he was in critical condition, police spokeswoman Tanya Little said.

About the same time, officers at Thomas Jefferson University Hospital learned of another Center City stabbing victim. This 27-year-old man had taken a taxi to the hospital from 1221 St. James St., near the other stabbing. He had been stabbed in the lower left abdomen "after an altercation," Little said.

Police have tied both attacks to one suspect, a man in his early 20s who they believe knew both victims.

Separately, police said a 36-year-old man was at home in the 5700 block of Market Street in West Philadelphia, in the company of a woman, when his ex-wife phoned at 3:09 a.m., and asked him to meet her at his front door.

When he opened the door, he was stabbed in the right shoulder with a small steak knife, Little said.

The victim was taken to Presbyterian Hospital and was in stable condition. The attacker ran off before police arrived. - Joseph N. DiStefano