Graphic bodycam footage released Tuesday by Republican Sen. Chuck Grassley shows local law enforcement and a Secret Service agent standing over the body of the gunman in the aftermath of the July 13 assassination attempt on former President Donald Trump during a campaign rally in Butler, Pennsylvania.

The footage, which Grassley said in a social media post was obtained via congressional request, was captured by the body camera of a Beaver County Emergency Services Unit officer.

It shows what appears to be multiple local law enforcement officers and a Secret Service agent standing on the roof from where the shots on Trump were fired from more than 400 feet away. The body of the gunman, 20-year-old Thomas Matthew Crooks, can be seen laying on the roof beside them with a trail of blood.

Last week, a local law enforcement officer with direct knowledge of the events had told CBS News that a sniper from a local tactical team deployed to assist the Secret Service at the rally had snapped a picture of the gunman and saw him looking through a rangefinder minutes before he tried to assassinate Trump.

In the bodycam video, an unnamed Secret Service agent appears to confirm this, saying that the deceased gunman matches the description of the suspicious person in photos that were disseminated prior to the shooting.

"A Beaver County sniper seen and sent the pictures out, this is him," the agent says in the video, referring to the shooter's body.

"I don't know if you got the same ones I did?" an officer asks the agent of the photos.

"I think I did, yeah, he's (the shooter) got his glasses on," the agent replies.

The officer adds that the sniper "sent the original pictures, and seen him (the shooter) come from the bike, and set the book bag down, and then lost sight of him."

The agent also asks about whether an abandoned bike that was found in the area belonged to the shooter.

"We don't know," an officer replies.

Sources previously told CBS News that an AR-style rifle, remote transmitter and cellphone were found on the shooter's body, while two explosive devices, a drone, a tactical vest and four magazines of the same ammunition used in the shooting were found inside the shooter's car.

In the video, the agent discloses that people who were believed to have filmed the gunman with their phones had been detained for questioning.

"There's people detained who were filming...maybe they were involved, maybe they weren't," the agent tells the officers.

Authorities have since confirmed that the gunman acted alone, and cellphone video has revealed that attendees attempted to alert officers to the shooter a full two minutes before he opened fire on Trump.

"I think we have three victims in the crowd, are you guys hearing that too?" the agent asks in the video, referring to the rally attendee, a 50-year-old retired firefighter who was killed, along with two other attendees who were critically wounded. 

During testimony Monday before the House Oversight Committee, Secret Service Director Kimberly Cheatle, who then resigned her post Tuesday, alleged that, at some point prior to the shooting, law enforcement teams were sent to identify and interview Crooks after he was deemed suspicious. She did not provide any additional details, including when the team was sent to make contact with him.

"At a number of our protected sites, there are suspicious individuals that are identified all the time," she said. "It doesn't necessarily mean that they constitute a threat."

However, three sources familiar with a July 17 law enforcement briefing to members of Congress said that Secret Service was notified by the Pennsylvania State Police of a suspicious person with a rangefinder on the ground at 5:51 p.m. — about 20 minutes before the gunman opened fire.

A CBS News analysis has determined that the gunman was able to fire eight rounds in under six seconds before he was fatally shot by a Secret Service sniper. 

— Scott MacFarlane, Melissa Quinn, Nicole Sganga and Anna Schecter contributed to this report. 

In:
• Pennsylvania
• Shooting
• Trump Rally
• United States Secret Service
• Donald Trump
• Politics
• Butler County