Alhinde Weems, 34, was charged with distributing cocaine and crack between December 2008 and January 2009.
In addition, investigators said Weems planned to use his authority as a police officer to rob another drug dealer.
However, he was arrested on his way to commit the crime.
Four guns were recovered from his home, along with ammunition and a homemade silencer.
Sentencing is scheduled for May 3, 2010.
Weems faces a mandatory minimum term of 15 years in prison with a maximum possible sentence of a life.
