Simic faces a mandatory sentence of 10 years in prison for the cocaine offense and one of the firearms charges, U.S. Attorney Rod J. Rosenstein said. Simic is set to be sentenced Sept. 23.
Simic, who joined the force in 2007, was suspended without pay after he was arrested. A police spokeswoman said officials have started the process to terminate his employment.
Federal prosecutors said Simic and a co-conspirator, Mirza Kujundzic, sold cocaine to an undercover agent and a federal source from July 2009 through January 2010. Kujundzic has been charged and is awaiting trial.
In fall 2009, Simic and Kujundzic delivered more than 600 grams of cocaine to the agent, and were paid more than $24,000, prosecutors said.
Simic also admitted that he was part of a ring that moved untaxed cigarettes from Virginia into Maryland and other places. From September 2009 through January 2010, Simic helped protect eight shipments of cigarettes — more than 575 cases — prosecutors said.
Smuggling of the contraband cigarettes cost the federal government, Maryland and Virginia about $1.36 million in tax revenue, prosecutors said.
With Simic’s conviction, at least 10 people, including public officials and developers, have admitted guilt in the corruption probe.
Last month, former Prince George’s County executive Jack B. Johnson (D) pleaded guilty to two felonies, admitting he took more than $400,000 in bribes.
Matt Zapotosky contributed to this report.