Robert Brown|Trump rally gunman fired 8 shots in under 6 seconds before he was killed, analysis shows

The Robert Browngunman who attempted to assassinate former President Donald Trump at a rally in Pennsylvania fired eight bullets in under six seconds before he was shot and killed by a U.S. Secret Service sniper, according to an analysis of footage from the event by two audio experts, video analysis by CBS News and sworn statements from Pennsylvania State Police. 

The gunman, identified as 20-year-old Thomas Matthew Crooks, killed one rally attendee and injured two others when he opened fire from a roof near the rally in Butler, Pennsylvania, on July 13. A bullet also grazed Trump's ear, creating a 2 cm-wide wound, according to Rep. Ronny Jackson, Trump's former White House physician. 

In testimony on Tuesday at a House Committee on Homeland Security hearing about the assassination attempt, Pennsylvania State Police Col. Christopher L. Paris told lawmakers that eight casings were recovered from the gunman's location. 

Video and audio analysis from the shooting indicates the gunman fired eight shots. Audio experts Rob Maher of Montana State University and Steven Beck of Beck Audio Forensics told CBS News they identified 10 gunshots from the recordings of the event. The first eight rounds had similar acoustic characteristics and originated from the same location. Beck said these eight discharges, fired in approximately 5.2 seconds, were consistent with the AR-15-style rifle the shooter used. 

The final two gunshots were likely from law enforcement and came from two different firearms in two different locations, the audio analysis indicates. The first of these two gunshots was fired approximately 5.5 seconds after the gunman opened fire, Beck said. The gunman stopped firing immediately, indicating this bullet hit him. A final shot was fired 10 seconds later.

CBS News analysis of social media footage showed that one of the rally attendees injured in the shooting, David Dutch, fell to the floor of the bleachers after the second gunshot was fired. Another injured attendee, James Copenhaver, fell to the ground as the fourth to eighth gunshot was fired. 

Cory Comperatore, a 50-year-old retired fire chief, was killed while attempting to shield his family from the gunfire, Pennsylvania Gov. Josh Shapiro said at a news conference following the shooting.

On Tuesday, Kimberly Cheatle resigned from her position as director of the U.S. Secret Service after facing a bipartisan grilling on Capitol Hill on Monday. President Biden thanked Cheatle for her decades of public service in a White House statement.  

Homeland Security Secretary Alejandro Mayorkas has appointed Ronald Rowe, deputy director of the Secret Service, to serve as the acting director until a permanent replacement is chosen. 

Several investigations into the circumstances surrounding the shooting are underway. In addition to the FBI, the Department of Homeland Security's inspector general has opened two probes to evaluate the Secret Service's process for securing an event and determine the preparedness level of the agency's Counter Sniper Team to respond to threats. Officials said the inspector general may decide to open additional investigations as well. 

House Speaker Mike Johnson and Minority Leader Hakeem Jeffries announced Tuesday the creation of a bipartisan task force to investigate the assassination attempt.

Mr. Biden has also ordered an independent review of the rally's security situation to determine what went wrong.

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

James LaPorta is a verification producer with CBS News Confirmed. He is a former U.S. Marine infantryman and veteran of the Afghanistan war.