Fuzzy video footage of Charlie Kirk’s alleged killer racing across a rooftop at Utah Valley University, dropping to the ground and sprinting away in the moments following the conservative activist’s death on Wednesday, was taken from so far away that it could not possibly have revealed his identity.
“You started off with a clip that made him look like an ant,” Donald Trump told Fox News in a Friday morning interview as the US president discussed the killing of the rightwing activist at a campus speaking engagement attended by thousands of students.
But the value to FBI investigators of the public release of the video at about 8pm local time on Thursday night, along with a series of high-definition images of the suspect, was beyond measure. It set into motion a rapid series of events that ended just three hours later with the arrest of 22-year-old Tyler Robinson, who authorities say was identified by a close relative – believed to be his father, a veteran sheriff’s deputy.
Related: Charlie Kirk shooting suspect: details of messages and gun casings emerge
The relative confronted him, elicited a confession, then alerted a family friend who turned him in, the Utah governor, Spencer Cox, revealed at a press conference on Friday.
Experts say the imagery “supercharged” the progression of an investigation that had appeared to stumble at a senior level in the first 24 hours after Kirk’s shooting, with the FBI director, Kash Patel, twice announcing, then retracting, that the person believed to be responsible had been caught.
The publication of the video was “designed to get people’s attention” to the enhanced photographs that showed the person in much greater detail, Andrew McCabe, the FBI’s former deputy director, told CNN.
“It was that release that put the crowd sourcing and the public identification of this guy into high gear. It paid dividends,” he said.
Patel gave a timeline of developments at the Friday briefing, after flying to Orem, Utah, the day before with his deputy, the former conservative podcaster Dan Bongino. The New York Times reported that the pair were involved in a “tense” online meeting on Thursday with about 200 FBI agents to talk about the faltering manhunt, and were determined to prove “they were up to the task”.
“In 33 hours, we have made historic progress for Charlie,” Patel told reporters, after opening his remarks with fulsome personal praise for Trump. “A case like this cannot be solved, cannot be brought, without partnering with your state and local authorities.”
According to Patel, calls to investigators with information were plentiful, and had reached 11,000 in number by Friday morning. “Every one of those leads will be run out,” he promised.
Most of the details, however, came from Cox, a Republican who ended his own comments with an impassioned plea for young people to turn away from what he called the “cancer” of social media and to “log off, turn off, touch grass, hug a family member, go out and do good in your community”.
Cox was reluctant to draw a direct line from the release of the video and photographs to Robinson’s arrest, but acknowledged the events occurred within short order, and that “through some process the family came to know that this had happened”.
It was reported by some media outlets later on Friday that the suspect’s father, Matt Robinson, a 27-year veteran with Utah’s Washington county sheriff’s department, about 200 miles from the murder scene, told his pastor about his son’s confession, and it was the pastor who called it in.
“I want to thank the family members of Tyler Robinson, who did the right thing in this case and were able to bring him into law enforcement,” Cox said.
The governor said investigators worked furiously to process chunks of information about the suspect that were coming in rapidly, and from interviews with family members and “a roommate of Robinson” they built a picture of a young man so consumed by hate at Kirk’s upcoming campus visit that he constructed and enacted a plan to kill him.
Evidence, he said, included photographs of messages Robinson shared with the roommate on the social media platform Discord that mentioned “stating a need to retrieve a rifle from a drop point, leaving the rifle in a bush … wrapped in a towel”.
Crime scene investigators later retrieved a Mauser model 98, in .30-06 caliber, a type of bolt-action firearm, with a scope mounted on top of it, that Cox said was found wrapped in a dark-colored towel.
Equally alarming, the governor said, were messages on bullet casings found with the weapon.
He said three unfired casings featured engravings reading: “Hey fascist! Catch!”, “Oh bella ciao” and “If you read this, you are gay, LMAO [laughing my ass off]”.
Video footage from the university’s surveillance cameras had also assisted in identifying Robinson, a former student, through his gray Dodge Challenger, which was recorded driving on to the campus at 8.29am on the morning of the shooting, Cox said.
The suspect also changed clothes twice, the governor asserted. He said Robinson was spotted arriving in a maroon-colored shirt, switched into darker clothes to commit the murder, then reverted to his original outfit, which he was still wearing at the time of his arrest late on Thursday.
“We’re grateful for everyone who worked together in such a short amount of time to find this person and to bring justice,” Cox said.
“This is a very sad day for our country, a terrible day for the state of Utah, but I’m grateful that at this moment we have an opportunity to bring closure to this very dark chapter in our nation’s history.”