WEST DEPTFORD TWP.  — When the U.S. Marshal’s Service agents went to serve a warrant on William Schickel for violation of probation, they positioned agents in the front and rear of the townhouse at 1083 Buckingham Drive.

It was 1:20 p.m. when a marshal, acting on a tip that Schickel, 24, was staying at this residence, knocked on the door, police said. The marshal asked the residents to come out and they told him Schickel, who lives in the White Swan trailer park on Mantua Grove Road, was in the basement.

A marshal called out, announcing their presence, but, at that moment, they heard what sounded like a gunshot, said police.

The marshals withdrew and maintained the front and back perimeter, police said, and called township police.

After several hours of trying to establish contact with Schickel, police and the Gloucester County Special Weapons and Tactics team put a robot into the townhouse, but it failed to spot Schickel, said police.

They then called in the Camden County Bomb Squad, which has a more-sophisticated robot.

At 6:15 p.m., there was still no contact with Schickel, police said.

Buckingam and Normandy Way remain closed.

“We don’t know where he’s at right now,” said Police Chief Samuel DiSimone.

An emailed letter was sent to parents from the West Deptford Township school district Monday afternoon, advising that a "police situation" was taking place "on Buckingham Drive in the Grande Townhomes. The police have asked us to hold all students who live either on Buckingam or on Moore Road. We have done that, and those parents have been contacted directly. All other students are being dismissed at their regular times."