A suspected robber was hospitalized last night with a gunshot wound received during the alleged holdup of a man in Collier, Allegheny County police said.

Three people, including the intended robbery target, have been arrested, and a fourth arrest is pending, police said.

The would-be robbery target, Joshua Oravetz, 21, of Scott, called 911 at 8:04 p.m. to report the robbery on Boyds Run Road in Collier.

The suspected robbers had fled by the time police arrived. One of them, Dupree Patterson, 31, of McKeesport, had been shot in the forearm and thigh.

His companions drove him to St. Clair Hospital for treatment.

County police Lt. William Palmer said Mr. Patterson and the two others, Crystal Carson, 19, Bridgeville, and Michael Harshey, 21, Perrysville Avenue, tried to rob Mr. Oravetz at gunpoint.

However, Mr. Oravetz pulled a pistol of his own and began firing, causing his attackers to flee, Lt. Palmer said.

Police suspect Mr. Oravetz had been selling marijuana and that the other three tried to rob him of his money and drugs, Lt. Palmer said.

At the scene, Mr. Oravetz was arrested on charges of aggravated assault and illegal possession of a firearm; no drug-related charges have been filed.

At the hospital, Ms. Carson and Mr. Harshey were arrested on robbery charges.

All three were awaiting arraignment this morning.

Mr. Patterson was to be charged upon his release from the hospital, Lt. Palmer said.