A longtime top aide to Rep. Roscoe G. Bartlett who has considered running for his boss’s seat in 2012 has resigned, a Bartlett spokeswoman confirmed Thursday, adding a new layer of intrigue to the state’s most compelling political contest.

Bud Otis, who has long served as Bartlett’s chief of staff and top campaign aide, submitted his resignation Wednesday night, Bartlett spokeswoman Lisa Wright said in a statement. The decision followed rumors that Otis was considering a run for the seat.

“Last night, Congressman Bartlett accepted Bud's resignation,” Wright said in an e-mailed statement. “He agreed with Bud that the multiple recent news reports about Bud's activities made it impossible for Bud to continue to serve him and the residents of the Sixth District of Maryland effectively.”

Rumors had floated for weeks that Otis would consider running for the seat, particularly if Bartlett decided to retire. Bartlett has said he is running for another term, but he has not raised much money. The 85-year-old would likely face the toughest race of his political career because of a new district that includes more Democratic voters.

Otis was not immediately available for comment.

Rumors of Otis’s candidacy were first reported in the Red Maryland blog, and they were cited by the state’s GOP chairman Thursday. Alex Mooney noted the reports that Otis was considering a run as he announced that he, too, will consider seeking the seat.

If everyone considering a run stays in the race, it would set up a GOP primary between a sitting congressman, his former longtime aide and his state party chair.