Wisconsin Republicans’ 14-month investigation into the 2020 election results, which cost taxpayers $1.1 million and turned up no evidence of significant fraud, ended on Friday when the top G.O.P. lawmaker who first announced the inquiry fired the man he had entrusted to lead it.

Under pressure from former President Donald J. Trump and his allies, Robin Vos, the Republican speaker of the State Assembly, had moved in June 2021 to hire Michael J. Gableman, a conservative former Wisconsin Supreme Court justice, to scrutinize the state’s 2020 results.

But after weeks of open tension between Mr. Vos and Mr. Gableman — partly over the speaker’s refusal to entertain decertifying Joseph R. Biden Jr.’s victory in the state, and partly over Mr. Gableman’s endorsement of a primary challenger to Mr. Vos — the speaker said he was shutting down the investigation. The firing was first reported by The Associated Press.