A former federal police officer is set to plead guilty to trying to manufacture methamphetamine at a federal science lab in the Washington suburbs.

Forty-one-year-old Christopher Bartley is scheduled to appear in U.S. District Court in Greenbelt, Maryland, on Friday. His lawyer says Bartley will enter a guilty plea.

The explosion occurred July 18 on the campus of the National Institute of Standards and Technology in Gaithersburg.

Defense attorney Steven VanGrack says Bartley wasn't trying to make methamphetamine for his personal use. Instead, VanGrack says Bartley was "conducting an unauthorized training experiment which failed." He says his client wanted to learn more about how meth is made in order to train the officers he supervised.

Bartley admitted his responsibility for the explosion and resigned the day after it occurred.