WASHINGTON — A former FBI agent in the Washington, D.C., field office has been indicted on 64 charges involving allegations that he tampered with substantial amounts of drug evidence, kept heroin seized during investigations in his car, and periodically took the drug.

The charges, including obstruction of justice and heroin possession, were filed against 33-year-old Matthew Lowry in federal court in Washington on Friday.

Lowry’s attorney did not immediately respond to a message seeking comment about the charges.

A nearly 70-page indictment provides the most detailed account of the allegations against Lowry. The charges against him caused federal prosecutors to dismiss charges against at least 28 defendants and notify 150 more that Lowry had participated in investigations targeting them.

If convicted, Lowry would face more than seven years in prison.