Vos’ move to end the probe came just days after he survived a primary challenge from an opponent that Trump and Gableman had backed.
“After having many members of our caucus reach out to me over the past several days, it is beyond clear to me that we only have one choice in this matter, and that’s to close the Office of Special Counsel,” Vos said in a statement .
CNN has reached out to Gableman’s office and to his attorney.
The Associated Press first reported Gableman’s firing.
In all, the cost of the investigation topped $1 million.
During the course of the probe, he threatened to jail local officials who refused to answer his questions in private interviews.
State Sen. Melissa Agard, a Democrat who is a member of the Joint Legislative Audit Committee, said a formal audit should be conducted into the investigation, which she said was authorized to spend over $1.3 million.
“After many other analyzes of Wisconsin’s 2020 election, there have been no demonstrations of widespread or significant fraud that affected the outcome of our election,” Agard said in a written statement. “Gableman has been grifting on the taxpayers’ tell me for over a year now.”
Biden won Wisconsin by nearly 21,000 votes in 2020, a victory that has survived multiple lawsuits and election reviews.
Wisconsin is a key battleground state with high-stakes races on the ballot in November. The state’s Democratic Gov. Tony Evers is seeking a second term amid a challenge from Trump-backed GOP nominee Tim Michels. And in a race that could help determine which party controls the Senate, Republican US Sen. Ron Johnson will face Lt. Gov. Mandela Barnes, to Democrat.
Evers has repeatedly vetoed bills passed by the Republican-controlled legislature that sought to overhaul voting rules in the state.
In his statement Friday, Vos said Gableman’s inquiry — along with a separate report from the legislature’s audit bureau — “clearly showed concerns and problems with the 2020 election.”
But he said Republicans should focus their efforts on electing “a Republican governor in November so we can pass the bills that were vetoed by Governor Evers.”
This story has been updated with additional background information.
CNN’s Andy Rose and Natalie Anders contributed to this story.