A day after President Trump gave a long-sought endorsement to Sen. Luther Strange, a wealthy businessman submitted complaints to Alabama's ethics commission and the Senate ethics committee, alleging malfeasance in Strange's Senate appointment.

Developer Stan Pate says he spent $100,000 in Facebook ads branding Strange's appointment as part of a corrupt bargain with former Gov. Robert Bentley, and says he's concerned about the potential impact of Trump's tweeted endorsement.

"When the president tweets, obviously in Alabama — if you look at his popularity — people listen," Pate says.

The complaint is a last-ditch effort to revive the issue ahead of a contest next week between Strange and fellow top-tier candidates Rep. Mo Brooks and Roy Moore, the former state supreme court chief justice. There will be a runoff election if no candidate tops 50 percent.

Pate says he's donated to both Brooks and Moore and feels either would be acceptable.

Strange, Alabama's former state attorney general, was made a senator in February by Bentley while the embattled governor was under criminal investigation by Strange's office as part of a complex scandal involving campaign funds and a mistress who worked as an adviser. The seat became vacant by Jeff Sessions resigned to serve as attorney general under Trump.

In November, Strange had requested that the state legislature pause impeachment proceedings against Bentley pending "related work" by his office. He later expressed interest in the appointment and refused to acknowledge his office was probing the governor.

When Strange was appointed, Bentley was able to pick a new state attorney general. The ultimate selection, Steve Marshall, confirmed an investigation into Bentley and appointed a special prosecutor, who negotiated a plea deal in exchange for Bentley's resignation.

Strange has maintained that, despite appearances, he did nothing wrong.

Pate likens the appointment to a bribe, however, saying "if I offered a traffic cop $50 to walk away from a traffic stop, I'd go straight to jail."

The complaint alleges that "[c]ommon sense is that a deal was agreed upon by then Governor Bentley and then Attorney General Strange - an unethical and illegal act by the two parties."

Pate emailed the Washington Examiner a notarized copy of the complaint, which he says he will also be sending to other sitting U.S. senators and to the Senate ethics committee, which says it performs preliminary inquiries on most referrals regardless of source.

Strange backers point out he requested that impeachment proceedings be stalled days before Trump's election victory, which led to the vacancy for Jeff Sessions' seat, and that he made clear he would have challenged anyone else who received the appointment.

In a statement, Strange spokeswoman Shana Teehan emphasized Pate's historical opposition to Trump.

"Stan Pate's NeverTrumper reputation speaks for itself," she said in a statement. "If Pate's against him, then Senator Strange is the perfect person to help President Trump drain the swamp in Washington, as evidenced by the president's ringing endorsement of the Senator."

Despite an intense lobbying effort and hefty establishment GOP support, Trump resisted pressure to endorse Strange until Tuesday, when he tweeted: "Senator Luther Strange has done a great job representing the people of the Great State of Alabama. He has my complete and total endorsement!"

Although the Alabama Ethics Commission's work outside of public meetings is opaque, the body played a significant role in Bentley's downfall, referring to prosecutors possible charges before the special prosecutor negotiated Bentley's plea deal in April.

Suspicion about Strange's interaction with Bentley is widespread but unproven.

Animosity among Republican factions in the state has deep and complicated roots, including hard feelings over Strange's successful corruption prosecution against former Alabama House Speaker Mike Hubbard, who was sentenced last year to four years in prison.

Strange opponents say there's enough of a basis for a criminal probe of the senator.

Republican state Rep. Ed Henry alleged in April that he had a conversation with Bentley on the day he appointed Strange and that he was told by the then-governor that he'd appoint Strange "to get rid of him" because "he's corrupt." Bentley denied the conversation happened.

Henry recently has refused to comment on whether he has been interviewed by federal or state investigators, citing the advice of his attorney

"It would be more shocking to me if there's not an investigation regarding the circumstances involving this appointment," says Mike Ball, chairman of the Alabama House of Representatives' ethics and campaign finance committee.

"There's a lot that needs to be aired out and probably won't be aired out before the election," Ball says. "If President Trump knew what I know [about Strange] he'd run from him like a scalded dog."

Ball, who has not endorsed a candidate in the primary, says he believes there may be a much deeper tangle of issues involving Strange dating to the prosecution of Hubbard.

At the time of Bentley's resignation, Brooks said the plea deal "concludes the investigation as to the former governor, but does not necessarily conclude the investigation." A spokesman for the attorney general's office, Mike Lewis, has declined to say if Brooks' work continues or whether it affects Strange.

Thomas Loftis, a spokesman for the FBI's Mobile office, which has jurisdiction over the state capital, declined to confirm or deny there is any investigation of Strange's appointment.

The Brooks and Moore campaigns did not immediately respond to requests for comment.

In addition to the new complaint, Strange faces similar allegations in an Alabama Bar Association complaint filed earlier this year by adoption attorney Sam McLure, who is seeking his disbarment.

A recent transfer of about $1,400 from Strange's federal Senate campaign and his dormant state attorney general campaign led to another state ethics complaint, referred by the office of Alabama Secretary of State John Merrill, also a Republican. Strange's campaign said it was seeking to comply with federal law by paying for websites formerly maintained by the state campaign.

The ethics commission was originally scheduled to hold a meeting on Aug. 2, but moved the date to Aug. 16, a day after the primary election.

Thomas Albritton, executive director of the Alabama Ethics Commission, says the meeting date was moved to accommodate a commissioner traveling outside of the country.

Merrill says he has not publicly shared an opinion on the nature of Strange's appointment, but that "I know this is an issue Sen. Strange has had to spend an inordinate amount of time on, and I am not surprised that issue was introduced by his opponents or by people who appear to be objective in the process."

Bentley set a 2018 special election date for Strange to face re-election. After Bentley's ouster, his successor Gov. Kay Ivey decided Bentley misinterpreted state law to Strange's advantage and moved the election to this year.