The Secret Service reveals communication failures during the assassination attempt on Trump in Pennsylvania.

AP - Communication failures with local police hindered the response of the United States Secret Service (USSS) before the assassination attempt on former President Donald Trump in July, according to a new report published on Friday. The report reveals a list of missed opportunities to stop the armed suspect who opened fire from an unsecured rooftop.

A five-page document summarizing the main findings of the USSS report identifies errors made by both local and federal law enforcement and highlights the broad and significant failures that preceded the July 13 shooting at a campaign rally in Butler, Pennsylvania, where Trump was grazed in the ear by a bullet.

While the failed response has been well-documented through congressional testimony, media investigations, and other public statements, the report marks the USSS's most formal attempt to catalog the day’s errors. It comes amid renewed scrutiny following the arrest on Sunday of a man in Florida who, authorities say, intended to assassinate Trump.

"It’s important that we hold ourselves accountable for the failures of July 13 and use the lessons learned to ensure that another failed mission like this never happens again," said Acting USSS Director Ronald Rowe Jr. in a statement accompanying the release of the agency's internal investigation report.

The report details a series of communication breakdowns before Thomas Matthew Crooks, 20, fired at Trump’s location from a rooftop less than 150 yards away and was subsequently shot by a USSS sniper. The document makes clear that the USSS was aware even before the attack that the rally site posed a security risk.

Among the identified problems, some local police officers at the scene were unaware that there were two communication centers on site, meaning officers didn’t know the USSS was not receiving their radio transmissions.

The police were also relaying crucial information outside of the USSS radio frequencies. While officers searched for Crooks before the attack, details were communicated "via mobile/cell phones in a staggered or fragmented manner" instead of over the USSS’s network.