American Crossroads, the conservative group founded by GOP strategist Karl Rove, is rehashing Sen. Claire McCaskill's (D-Mo.) private plane saga with a combination of radio ads and billboards.

Unpaid back taxes on a private plane owned by McCaskill caused major political problems for the senator in March and gave Republicans fodder to portray her as out of touch and elitist. McCaskill eventually repaid almost $300,000 in taxes and said she would sell the plane.

The radio ad simulates a detective drama, interjecting sound bites from McCaskill's public statements as if she were responding to interrogation by a detective.

"I was working the truth squad out of St. Joe Airport. I found Sen. Claire McCaskill standing next to a fancy private jet," the narrator says sardonically.

"I made a huge mistake," McCaskill says.

The ad ends with the detective handing down a sentence of "guilty, for violating our trust."

The billboard, for fictional airline "AirClaire," shows McCaskill in a flight attendant-style outfit and suggests that while high air fares might be a downer for the general public, they don't affect McCaskill.

The Democratic Senatorial Campaign Committee blasted the ad and GOP strategist Karl Rove, one of the founders of American Crossroads.

"Karl Rove and his anonymous billionaires are at it again with blatantly inaccurate commercials about Claire McCaskill,” DSCC spokesman Matt Canter said in a statement. 

“The bottom line is that Claire self-reported, fully corrected any mistakes and hasn't stepped foot on the plane since. Karl Rove and out-of-state special interest groups are going to use this issue like a piñata, but it won't work," Canter said. "These Washington groups simply don't like that Claire is an independent moderate who fights for Missouri’s working families – not the special interests."

McCaskill, a fiscally conservative Democrat who took her seat from a Republican in 2006 by a slim margin, is considered one of the most vulnerable senators up for reelection in 2012.

This isn't the first time American Crossroads has gone after her. Earlier this year the group launched radio ads against McCaskill and put up a website arguing that she's more liberal than she makes herself out to be.

This post was updated at 4:37 p.m.