PENNSVILLE — A former Pennsville police officer was arrested and charged Wednesday with impeding and obstructing an FBI investigation of his alleged possession of child pornography, federal authorities said.

Robert Waterman, 31, of Wrightstown, Burlington County, destroyed a computer hard drive in March 2010, while employed as a police officer, after FBI agents began investigating him in connection with possession of child pornography, U.S. Attorney Paul J. Fishman said in a statement Wednesday.

According to Fishman’s office, which cited a criminal indictment unsealed Wednesday, FBI agents began investigating Waterman on March 4, 2010. While interviewing him that day, authorities allege, the agents told him of the nature of their investigation.

On the same day, authorities say, Waterman destroyed a computer hard drive with the intent to impede and obstruct the investigation. Authorities recovered the hard drive the next day, according to the indictment.

Waterman, who appeared Wednesday before U.S. Magistrate Judge Joel Schneider in Camden, is charged with one count of obstruction of justice. He faces a maximum of 20 years in prison if convicted.

The former cop hasn’t been charged with possession of child pornography, Fishman’s office said Wednesday.

A call to Waterman’s public defender was not returned.