Updated: 3:10 p.m.

A longtime aide to Sen. David Vitter (R-La.) resigned Wednesday after a news report detailed his 2008 arrest for attacking his ex-girlfriend with a knife.

ABC News reported that Brent Furer, a legislative aide for Vitter, was arrested after a 90-minute altercation with his ex-girlfriend during which he threatened to kill her and refused to let her go. He eventually pleaded guilty to three misdemeanor charges, including threatening harm and destruction of property.

Vitter did not fire Furer after the incident, though he suspended his pay for a few days, according to ABC News. But Furer was brought back on staff after he was sentenced with probation and community service.

Democrats could use the incident to further disparage Vitter’s attitude toward women in the Louisiana Republican’s re-election campaign. Vitter faces Rep. Charlie Melancon (D), whose campaign has attacked Vitter for his connection to the “D.C. Madam” prostitution ring. Vitter was found on the escort service’s phone list in 2007 and later apologized for his actions.

Vitter spokesman Joel DiGrado said Vitter hired Furer on “very strong recommendations, including those related to his military service in Kuwait.”

Vitter allowed Furer to return to the office once he was sentenced in the 2008 incident after consulting with the Congressional employment office and taking “further significant disciplinary action,” DiGrado said. But he said the lawmaker was not aware of other legal trouble detailed in the ABC News report — including an open warrant for a drunken driving charge in Baton Rouge.

“Sen. Vitter accepted the employee’s resignation today after learning of the other incidents,” DiGrado said in an e-mail Wednesday.