The NFL is investigating an accusation of domestic violence against line judge Carl Johnson, who was once the league's vice president of officiating.

"The matter is under review under of the league's personal conduct policy," a league spokesman said Tuesday.

All league employees are subject to discipline under the league's domestic violence policy, which establishes a six-game suspension for a first offense. Mitigating circumstances can increase or decrease that game total.

TMZ Sports first reported the allegations, made earlier this year in Louisiana by a woman Johnson was living with. She filed for a restraining order in July, according to a spokesperson for the Lafourche Parish Clerk of Court, but the request was dismissed July 21. The woman has appealed the decision.

A representative for the Lafourche Parish Sheriff's Office told TMZ Sports that the case is still under investigation.

Johnson was the NFL's top official from 2010 to '12 before returning to the field as the league's first full-time official. He dropped full-time status a few years later and was not among the 21 full-time officials announced by the league earlier this month.

Johnson is part of referee Terry McAulay's crew and worked Sunday's game between the Philadelphia Eagles and Kansas City Chiefs at Arrowhead Stadium.