Sen. Ron Johnson accused the FBI and Secret Service of stonewalling a Senate probe of last month’s assassination attempt against former President Donald Trump.

Johnson (R-Wis.), who is part of a bipartisan Senate investigation into the attempt on Trump’s life, argued that the bureau and Secret Service have complicated the probe by giving them redacted documents, often on the day of key interviews.

“All I can really tell you is the Secret Service, FBI are basically dragging their feet. They’re stonewalling us,” Johnson vented on Fox News’ “Sunday Morning Futures.”

“We’re not getting squat, from my standpoint, from the Secret Service or the FBI. We have requested all their 302s, their transcriptions of their interviews with hundreds of individuals. They’re not turning those over to us as well.”

A bevy of organizations is probing how Thomas Matthew Crooks, 20, was able to crawl up onto a rooftop on July 13 and fire off eight shots, including one that clipped and drew blood from Trump’s right ear.

The shooting killed firefighter Corey Comperatore, 50, and left two other rally attendees — David Dutch, 57, and James Copenhaver, 74 — severely wounded. Crooks was killed by law enforcement.

“If you want to design an investigation to raise suspicions and drive conspiracy theories, this is exactly how you do that investigation,” Johnson added. “It was just jaw-dropping that they released the body for cremation before anybody’s seen any autopsy or toxicology reports.”

“It’s just driving suspicion and conspiracy theories.”

Senate Homeland Security and Governmental Affairs Committee Chair Gary Peters (D-Mich.) is helming an inquiry into the assassination attempt in the upper chamber. Johnson was previously chair of that committee.

Additionally, there are investigations from the newly minted bipartisan House task force and the Department of Homeland Security’s Office of the Inspector General.

The Secret Service has come under intense scrutiny over the security failings that preceded the attack.

The fateful rally in Butler, Pennsylvania marked the closest a gunman had come to killing a sitting or former US president since the 1981 attempt against former President Ronald Reagan.

Kimberly Cheatle stepped down as Secret Service director last month amid a wave of political pressure. At least five officials at the protective agency also were moved to administrative duty — meaning that they can’t be involved in operational planning — over the debacle, ABC News reported.

The Post contacted both the FBI and Secret Service for comment.

“They’re the only ones that are going to have access to this information until they decide what information to give us and when to give it to us. They’re in total control,” Johnson further groused.

The FBI said any suggestion the bureau was “interfering” with the congressional probe of the assassination was “inaccurate and unfounded.”

“We have followed normal procedures in the handling of the crime scene and evidence. The FBI continues its painstaking work on the investigation to develop as complete a picture as possible of what led to the shooting, and we remain committed to maximum transparency as we continue to share information with Congress,” a bureau spokesperson told The Post when asked about Johnson’s remarks.

As for Johnson’s complaints about Crooks’ body being released for cremation, the spokesperson argued that was, “in keeping with normal procedures.”

The Senate is currently on recess but slated to return next month.