PHILADELPHIA -- The Philadelphia police commissioner says he's concerned about tactics used during an overnight traffic stop that left an unarmed driver dead. It was one of two police shootings the same night.

Commissioner Richard Ross called it "an unfortunate incident all the way around."

He says an officer was on foot when the driver refused to stop his minivan and then attempted to drive off following the stop just before 1 a.m. Wednesday.

Get Breaking News Delivered to Your Inbox

Ross says the officer was trapped "between the car and some other area where he didn't feel like he could escape," and fired his weapon.

The driver was identified Monday as Richard Ferretti, 52, of Andreas, about 80 miles north of the city.

Police had received several calls from college students living in the area concerned about the driver and observed the vehicle circling the block several times, authorities said.

Ross said he's "somewhat concerned about the tactics... but we've got a lot of work to do on this investigation. It's an unfortunate incident all the way around."

Investigators say an officer fired four shots, one striking Ferretti in the chest. After he was shot, his van struck several cars before coming to rest, CBS Philadelphia reported. No weapon was found in Ferretti's vehicle, according to police.

Ross says the department has strict policies banning officers from firing into vehicles unless their lives are in danger.

CBS Philly

The officer involved, who Ross confirmed had been dragged down the street by a suspect in a car he was trying to stop several months ago, and had recently returned to work, has now been placed on administrative duty pending the outcome of the department's preliminary investigation, CBS Philadelphia reported.

Police planned to interview all parties and search for other witnesses as well as surveillance video, police said.

"It's very early in the investigation," Ross said. "I'm not making any judgments about the investigation -- whether it's good or bad -- at this particular time. We're going to have to see."

In a separate confrontation late Tuesday night in southwest Philadelphia, police shot and wounded a man after officers said he refused to drop a gun.

Officers said they heard gunshots and saw a man firing into the air, and he fired at officers and missed before they returned fire. He was hit in the leg and was hospitalized in stable condition Wednesday.