A US Secret Service investigation found communication gaps and a lack of diligence ahead of the attempted assassination of Republican presidential nominee Donald Trump in July at a rally in Butler, Pennsylvania.

A bullet grazed Trump's ear in the attack, two rally attendees were wounded and one was killed. The shooter was killed by a Secret Service countersniper, but only after he had fired eight rounds in total. 

"While some members of the advance team were very diligent, there was complancency on the part of others that led to a breach of security protocols," Secret Service Acting Director Ronald Rowe said at a press conference on Friday. He said agency employees would be held accountable where appropriate.

Rowe stepped into the job after Secret Service Director Kimberley Cheatle resigned in the aftermath of the assassination attempt. The US Secret Service is responsible primarily for protecting presidents, vice presidents, presidential candidates and visiting dignitaries.

What did the review find? 

Rowe said the Secret Service review "identified deficiencies in the advanced planning and its implementation by Secret Service personnel."

These included poor communication with local law enforcement, an "over-reliance" on mobile communication devices "resulting in information being siloed," and line of sight issues, which "were acknowledged but not properly mitigated." 

"At approximately 18:10 local time, by a phone call, the Secret Service security room calls the countersniper response agent reporting an individiual on the roof of the AGR building," Rowe said. "That vital piece of information was not relayed over the Secret Service radio network."

The report attributed this to organizational and communication failures involving both local police and the Secret Service, with local law enforcement broadcasting vital information on the shooter on a radio frequency to which the Secret Service did not have access. 

"The failure of personnel to broadcast via radio the description of the assailant, or vital information received from local law enforcement regarding a suspicious individual on the roof of the AGR complex, to all federal personnel at the Butler site inhibited the collective awareness of all Secret Service personnel," the report said.

This shortcoming particularly hampered Trump's protective detail, who might have elected to halt Trump's speech and move him prior to shots being fired had they known about other officers' trying to locate and respond to a suspicious individual around 150 meters (roughly 500 feet) away. 

Compounding matters, the roof used by the shooter had been identified beforehand as a possible danger and deployment site but this did not lead to a response. A tactical team from local police was posted on the second floor of the building, but not on the roof, and the Secret Service was not aware of this.

It's standard practice for local law enforcement and the much smaller Secret Service to cooperate at such large events.

Congress unanimously approves Secret Service funding boost

Meanwhile, the US House of Representatives unanimously approved a bipartisan bill on Friday designed to boost protection for presidential election candidates. It passed by 405 votes to zero and should clear the Senate with similar ease. 

The bill requires the Secret Service to provide the same protection to major candidates in an election as it does to sitting presidents and vice presidents.

The legislation was introduced on July 23, 10 days after the shooting in Butler, Pennsylvania. 

Most of the details outlined by Rowe had already come to light via a combination of Congressional testimonies, media reporting, and other public statements, but Friday's five-page report is the Secret Service's most direct attempt to catalog the errors of the day. 

It also comes amid fresh scrutiny following the arrest of a man last Sunday who had been lying in wait at Trump's Florida golf course with a rifle and who investigators believe planned to try to shoot Trump. 

In that instance, the Secret Service has said that the shooter never had a line of sight on Trump and never fired a shot in his direction.

Agents identified and engaged the suspect while scouting ahead of Trump; he fled the scene but was soon apprehended.

msh/sms (AFP, AP, Reuters)