Mayor Gray's chauffeur, Mark Long, is 6th person to plead guilty to violating campaign finance laws

Vince Gray during the 2010 mayoral campaign. (AP file photo)

WASHINGTON (AP/WJLA) - A former D.C. Council candidate who served as driver for District of Columbia Mayor Vincent Gray during his 2010 campaign has pleaded guilty to conspiring to violate campaign finance laws.

Prosecutors say Mark Long acknowledged Friday as part of a plea deal that he knew payments made to him were being concealed from officials. He faces one to 12 months in prison or probation.

A charging document says Long was paid by a public-relations firm to serve as Gray's driver and that those payments weren't reported to campaign-finance officials. It also says Long was involved in a scheme to pay another candidate to drop out of the race and endorse Gray. The document does not identify Gray by name, but prosecutors have previously named him in court in related cases.

Long, who unsuccessfully ran for a council seat in 2008, is the sixth person to plead guilty to charges involving the 2010 election. An investigation after Gray's election uncovered a $653,000 slush fund never reported to campaign-finance officials that helped Gray get elected. Gray has not been charged with a crime and has denied all wrongdoing.

Long's attorney did not immediately return a message seeking comment.