A shadowy outside Super PAC is taking aim again at U.S. Sen. David Vitter in the governor’s race.

Ten days after launching its first ad against him, the unknown group called the Louisiana Water Coalition is attacking Vitter for keeping an aide on his Senate staff for two years after the aide was arrested and accused of slashing his girlfriend.

Among the responsibilities of the aide, Brent Furer, were women’s issues, according to 2010 news accounts.

With a backdrop of ominous music, the ad says the episode shows that Vitter cannot be trusted.

Furer left Vitter’s staff in 2010 after ABC News reported the existence of the 2008 attack and that Furer had an open warrant for his arrest on a drunk driving charge in Baton Rouge. ABC reported then that Furer resigned after the network broke the story. In fact, the Vitter campaign said 10 days ago, “Senator Vitter fired the staffer in question when he found out all the facts.”

The attack came when Furer’s girlfriend attempted to leave his apartment, according to the Washington, D.C. police report.

The new ad notes that Furer ended up pleading guilty. It was to three lesser charges, including obstruction, attempted threats and destruction of property, The Advocate reported in 2010.

Furer’s legal troubles and work for Vitter were noted in the water coalition’s first ad, which gave greater attention to his 2007 prostitution scandal. The Vitter campaign’s attorney, James Garner, succeeded in knocking the first ad off the air because of the wording over Furer’s guilty plea. The water coalition got it back on the air a day later after tweaking the ad’s wording.

The Vitter campaign believes that trial lawyers are behind the ads, but this won’t be confirmed until the water coalition makes public its campaign finance report. It is due on Thursday.