Updated

Four security guards at a Washington-area federal center have been accused of selling weapons certifications to other guards who needed to pass weapons tests.

The guards, who worked at the National Oceanic and Atmospheric Administration headquarters in Silver Spring, Maryland, were arrested Tuesday after being indicted on several counts, including theft and extortion.

Prince George's County State's Attorney's Office spokesman John Erzen says the suspects were involved in a scheme in which they told guards they had failed their weapons tests but could pay hundreds of dollars to get the certification.

Erzen says at least seven guards agreed to pay. It's unclear whether they actually failed the tests, or whether they were lied to.

The guards were employees of North American Security, a company that was contracted to provide security at the building.