The fallout from Mark Sanford's Argentinian romance is getting increasingly nasty.

Yesterday, State Senator Jake Knotts, a Republican but a committed Sanford foe, sent a letter to fellow lawmakers, in which he accused unnamed supporters of the bed-hopping chief exec of planting a rumor that Lieutenant Governor Andre Bauer -- who would become governor if Sanford steps down -- is gay.

Read the letter here.

Knotts writes:

I can tell you with absolute certainty this attack was orchestrated on behalf of Mark Sanford, either directly or indirectly, and financially subsidized by him or one of his many "front-groups".

And speaking this afternoon to CNN, Knotts -- who earlier this summer played a key role in alerting the media to Sanford's disappearance, then stoking the story over the coming days -- addressed Bauer's sexuality in colorful terms:

"Ain't a homosexual bone in his body. That boy is a good boy. It's a just an attempt to prevent Andre from become governor.

Knotts adds in the letter that he is "100 % certain the rumor is false". Asked in June by The State newspaper whether he was gay, Bauer replied: "One word, two letters. No."

Knotts offers no hard evidence to support his claim that Sanford's supporters planted the rumor, but points out that Bauer last week called on Sanford to resign, and that over the weekend, House GOPers followed up on that by deciding all but unanimously to ask for Sanford's resignation. Two days later, the Bauer rumor appeared on the blog of Mike Rogers, a Washington D.C. gay activist known for outing people he says are in the closet. From there it was quickly picked up by South Carolina bloggers.

Knotts goes on to urge his fellow lawmakers "to move swiftly to rid our state of this
Governor," and calls for an investigation of the "attack" on Bauer.