GROTON, Conn. (AP) — The Navy’s submarine base in Groton, Conn., says 14 sailors have been implicated in an investigation into illegal drug use.

Base officials say the sailors may face state criminal charges as well as charges under the Uniform Code of Military Justice.

Six of the sailors have been charged so far. Two were arrested with marijuana after a traffic stop on April 30 and four others have been charged with attempt to possess the drug MDMA, also known as ecstasy.

The investigation involving Groton police and the Naval Criminal Investigative Service also led to the arrests of four civilian Rhode Island residents who were taken into custody on May 3.

The sub base says it has removed the implicated sailors from normal duty pending the investigation results.