Secret Service agents failed to ensure that proper safeguards were in place that could have obstructed Donald Trump’s would-be assassin’s view of the former president at his campaign rally in Butler, Pa., according to a scathing internal investigation.

Plans were discussed by agents with Secret Service headquarters and the Pittsburgh field office to potentially use cranes, trucks and flags to block the line of sight from the AGR International building – from which Trump’s would-be assassin opened fire – to the stage where the 45th president was shot, officials told the Washington Post.

Instead, Secret Service supervisors who showed up on site on July 13 found the heavy equipment and flags were placed in a way on the Butler Farm Show grounds that did not impede the view between AGR building and the stage, according to the investigation, the findings of which reportedly may be released next week.

The internal probe, ordered by Secret Service acting director Ronald Rowe, also found that the agency never instructed local police to secure the rooftop from which 20-year-old gunman Thomas Matthew Crooks tried to assassinate Trump.

Crooks, perched atop the building about 130 yards from the rally stage, had a clear line of sight when he fired off eight rounds, killing a rallygoer, wounding two others and striking Trump’s ear.

The gunman was then killed by a Secret Service counter-sniper.

In the immediate aftermath of the shooting, the Secret Service had insisted local police were responsible for securing and patrolling the factory grounds of AGR International – located outside of the rally grounds.

The internal investigation additionally detailed the alarming communication breakdown between federal and local authorities, according to the Washington Post.

The radio room used by Secret Service agents to field outside threats was unable to receive real-time alerts from local police stationed outside.

It has previously been reported that Crooks was spotted by law enforcement, using a rangefinder and looking at his phone, nearly an hour before Trump took the stage

According to the internal probe, Secret Service agents didn’t hear local police talking on their radios about trying to track down Crooks and then locating him after Trump began his remarks.

Agents on the ground got the message that Crooks was a “threat” just 10 minutes before Trump began speaking.

Rowe, the acting Secret Secret director, admitted to the Washington Post the agency must be held accountable for the security breakdowns highlighted in the report.

He also said the agency has launched another review to boost security for the dozens of government officials protected by the Secret Service.

Rowe briefed members of the Senate Homeland Security and Governmental Affairs Committee on the report Thursday and lawmakers from both sides of the aisle said they were “appalled” by the security failures at Trump’s rally.

“I think the American people will be shocked, astonished and appalled by what we will report to them about the failures of the Secret Service in this assassination attempt of a former president,” said Sen. Richard Blumenthal (D-Conn.), who chairs the panel’s Permanent Subcommittee on Investigations.