Boxes of documents containing personal information from the Walter Reed Army Institute of Research were supposed to be shredded but instead turned up last week in a trash bin, police said.

A resident of a suburban Washington neighborhood near the Army medical research's campus found the boxes Friday and alerted Montgomery County police.

The files were research study records, said Cynthia Vaughn, a public affairs officer for the U.S. Army Medical Command. An investigation was under way to determine precisely what information they held and why they appeared off base, Vaughn said Monday. Police said most were from the late 1990s and likely were placed in the bin on the same day they were discovered.

The records were supposed to be shredded by a Walter Reed research division employee.

The Silver Spring-based institute is the Pentagon's largest biomedical research laboratory and is not directly affiliated with the Walter Reed Army Medical Center in nearby Washington. Researchers at the facility work on issues such as tropical diseases and post traumatic stress disorder.

No foul play is suspected and no charges were filed. Police said they do not believe anyone had access to the information other than the person who found the records and called authorities.