Allegations surrounding Republican Rep. Michele Bachmann and her brief presidential campaign are getting further examination from the House Ethics Committee.

The panel said in a brief statement Friday it is extending until at least September a review of Bachmann’s case, which was referred to it by the Office of Congressional Ethics, an independent investigative body. The panel said it would announce any further action by Sept. 11.

The committee announced similar extensions of OCE investigations for three other members of Congress: Reps. Tim Bishop, D-N.Y., Pete Roskam, R-Ill., and John Tierney, D-Mass. The panel said it would announce further action on those cases, too, in September.

William McGinley, a lawyer for Bachmann, acknowledged the OCE investigation in March, saying it was tied to her presidential bid and that the tea party favorite was cooperating with the investigation. Bachmann has denied any wrongdoing but announced in May she would not seek re-election.

In a statement Friday, McGinley said the committee’s extension was routine and expressed confidence that Bachmann will be vindicated.

“Today’s statement by the House Ethics Committee emphasizes that its customary 45-day extension does not ‘indicate that any violation has occurred, or reflect any judgment on behalf of the Committee,’” McGinley said. “It does not speak to the merits of this matter, and any inference to the contrary is false.”

He added, “We are confident the committee will discover, upon proper review, that the highly politicized allegations made at the OCE level were baseless and without merit.”

The OCE is an independent House panel run by a board of directors who are outside Congress, although some of them are former lawmakers. The OCE’s investigative reports and recommendations for further investigation go to the member-run House Ethics Committee, the panel that decides whether rules were violated. The committee can then vote to continue investigations, launch its own formal investigations or dismiss cases outright.

OCE referred each of the investigations to the Ethics Committee in June, recommending full investigations. The House committee was required to take action on the cases or release the full reports of the OCE by Sunday. Instead, it will continue to look into all of the cases for another 45 days.

Because not all of the OCE reports were revealed Friday, it’s not clear what specifically some of the investigations of the lawmakers entail.

In a statement, Tierney said he believed the OCE investigation involving him was related to his personal financial disclosure reports.

“I welcome the opportunity to finally put this issue to rest after many years of my opponents attacking me,” Tierney said.

Bishop was criticized by his Republican opponent in 2012 for helping a constituent who later donated $5,000 to his campaign to obtain a fireworks permit.

“As I have said many times, I welcome a fair-minded review of the facts because I have done nothing wrong,” Bishop said.

Roskam’s office said in a statement the OCE investigation into him involved a trip to Taiwan. Roskam spokeswoman Stephanie Kittredge said he informed the Ethics Committee about the trip before he left and took the unusual step of publicizing his OCE report on Friday because he said he had done nothing wrong.

“The record reflects that Rep. Roskam fully complied with all laws, rules, and procedures related to privately sponsored travel,” Kittredge said. “The trip was vetted and approved by the House Ethics Committee, the body legally authorized to make determinations on congressional conduct.”

Bachmann’s White House bid ended quickly after a disappointing sixth-place finish in the Iowa’s lead-off presidential caucuses but has caused lingering problems for her.

In January, a former Bachmann aide sent a letter to the Federal Election Commission alleging that Bachmann made improper payments to an Iowa state senator who served as her state chairman. A suit by a different aide alleging that someone in her team stole a private email list of home-school supporters for use in the campaign was dismissed last month.

Earlier this month, Javier Sanchez, a former top aide to Bachmann, was arrested and charged with thefts that took place in a House office building. Sanchez has left Bachmann’s office and is charged with theft of money or goods less than $1,000 in value.