Rep. Mark Walker, R-Sandy, resigned and ended a House Ethics Committee investigation Monday into allegations he attempted to bribe his GOP primary opponent in his unsuccessful race for state treasurer.

Walker said in a letter delivered Sunday to House Speaker Greg Curtis, R-Sandy, that he had decided not to serve out the five months remaining in his term "(b)ecause I cannot in good conscience continue to put my family through the attacks and turmoil ... ."

After being advised by Legislative General Counsel John Fellows that the ethics committee no longer had jurisdiction over Walker after his resignation, members dismissed the complaint filed against him by five lawmakers and adjourned.

"Business as usual," complained one of the five, Rep. Phil Riesen, D-Salt Lake.

But the five lawmakers — including two Republicans — are considering filing a new ethics complaint against an unnamed legislator said to be involved in the alleged bribe. That legislator is widely rumored to be a member of House GOP leadership.

And a criminal investigation by two county attorneys appointed by Attorney General Mark Shurteff, a Walker supporter, continues into the allegations made by Walker's primary opponent, Richard Ellis. Ellis won the GOP runoff with nearly 60 percent of the vote.

Ellis, the chief deputy state treasurer, said Walker offered him the opportunity to keep his job at a much higher salary if he dropped out of the race. Walker has denied any wrongdoing but has said he told Ellis he wouldn't fire him or anyone in the treasurer's office if he won.

"To me, it seems like it validates my position, validates the allegations," said Ellis, who attended the ethics committee meeting to testify under subpoena. He said he was surprised to hear Walker resigned.

Before dismissing the complaint, one member of the ethics committee, Assistant Minority Whip Carol Spackman Moss, D-Salt Lake, pressed to continue the investigation to determine if any other lawmakers committed an ethics violation in connection with the allegations.

"Others may be guilty," Moss said. "I believe this hearing was in part to see if other people were involved. The fact that Rep. Walker resigned takes him off the table, so to speak," but doesn't affect any other lawmaker.

Fellows, though, said legislative rules would not permit the investigation to go forward now that Walker had resigned. Fellows said later in an interview that any further investigation would require a new complaint be filed against a specific lawmaker.

That's what the five lawmakers who came forward with the ethics complaint against Walker are considering, according to their legal counsel, David Irvine. "We're still exploring options, and there are several," Irvine said.