Authorities have taken into custody the person they suspect of shooting and killing conservative activist Charlie Kirk on Wednesday at a Utah university campus event.

Tyler Robinson, 22, was taken into custody in St. George, Utah, on Friday, authorities and sources told ABC News.

Robinson's father recognized him as the person being sought by police after authorities distributed photographs.

The father initially told Robinson to turn himself in. Robinson initially said no, but later changed his mind, officials said.

The father then called a youth pastor, who is also a U.S. Marshals task force officer. The officer advised the father to have Robinson stay in place.

At a press conference on Friday, Utah Gov. Spencer Cox said Robinson had become more political in recent years, and engaged in a conversation with a family member about Kirk's visit to the Utah Valley University campus the night before.

Cox also described what was engraved on the casings found on the scene.

The first casing, according to Cox, said "Notices Bulge OWO what's this??"

The other three unfired casing said: "Hey fascist! CATCH!" with an arrow symbol pointing up, then to the right, and then three arrows pointing down, "O Bella ciao, Bella ciao, Bella ciao, Ciao, ciao!," and "If you read this, you are GAY Lmao."

When law enforcement identified Robinson, they also interviewed Robinson's roommate who showed them a message between Robinson and his roommate.

"The content of these messages included messages affiliated with the contact Tyler, stating a need to retrieve a rifle from a drop point, leaving the rifle in a bush," Cox said. "Messages related to a to visually watching the area where a rifle was left, and a message referring to having left the rifle wrapped in a town. The messages also referred to engraving bullets and a mention of a scope and the rifle being unique. Messages from the contact Tyler also mentioned that he had changed outfits."

Cox said Robinson arrived on campus driving a gray Dodge Challenger, which matched his vehicle he arrived in on campus.

He also thanked Robinson's family, "who did the right thing."

FBI Director Kash Patel said that law enforcement caught Robinson within 33 hours of the shooting and was on scene within 16 minutes.

"This is a very much an ongoing investigation, as the governor said, and we will continue to work with state and local authorities to develop the investigation to provide them the evidence they need for their ongoing prosecutions," Patel said.

Authorities and a former FBI agent previously said they believed the subject to be a college-aged individual with an apparent proficiency in handling a high-powered rifle and likely knew the layout of the university where the homicide occurred.

President Donald Trump initially announced the arrest, stating on "Fox and Friends" on Friday morning, "I think with high degree of certainty, we have him in custody."

During a news conference on Thursday evening, state and federal officials released video of the person of interest jumping down from the roof of a building on the campus.

Beau Mason, commissioner of the Utah Department of Public Safety, said the suspect was wearing "distinct clothing" that could help in his identification, including Converse sneakers.

He said the person seen in the video jumping from the roof left shoe impressions and a palm print.

"We are investing everything we have into this and we will catch this individual," Mason said at the news conference.

Authorities had received more than 7,000 tips and leads and completed some 200 interviews, Utah Gov. Spencer Cox said.

During a news conference on Thursday morning, Robert Bohls, special agent in charge of the FBI's Salt Lake City field office, said investigators believe they have recovered the weapon used in what the governor of Utah on Wednesday called a "political assassination."

Bohls said the weapon, a high-powered bolt-action rifle, was found discarded in a wooded area near Utah Valley University (UVU) in Orem, and is being analyzed at an FBI laboratory for any clues that can identify the gunman.

More specifically, multiple law enforcement sources with knowledge of the investigation told ABC News that the weapon is an older model imported Mauser .30-06 caliber bolt-action rifle that was found wrapped in a towel in a wooded area near the school. The sources said a spent cartridge was discovered in the chamber of the gun.

The gun and cartridges recovered are to be flown to the FBI's main laboratory in Quantico, Virginia, for the most technologically advanced forensic analysis, law enforcement sources told ABC News. The focus is to look for any latent fingerprints and DNA, the sources said.

Investigators also collected a footwear impression, a palm print and forearm prints for analysis, Bohls said.

Mason said that investigators are also studying "good video footage" of the shooter that they have used to track his movements before and after the shooting.

Following Thursday's news conference, the FBI in Salt Lake City released surveillance images of the person of interest wanted in connection with the shooting. The images show a person who appears to be a white male, wearing all dark clothing, including a dark long-sleeved collarless top with what appears to be an image on the front that includes an American flag. The man in the images is also wearing a dark ball cap and sunglasses.

The FBI announced a $100,000 reward is being offered for information leading to the capture of the suspect.

Mason said investigators believe the suspect arrived at the UVU campus at 11:52 a.m. local time, about 28 minutes before Kirk, the CEO and co-founder of the conservative grass roots organization Turning Point USA, was shot. He said the deadly shot was fired from a building a substantial distance from where Kirk was speaking to a crowd, authorities estimate was about 3,000 people. He did not disclose which building the shooter fired from.

"We have tracked his movements onto the campus, through stairwells, up to the roof, across the roof to the shooting location," Mason said. "After the shooting, we were able to track his movements as he moved to the other side of the building, jumped off of the building, and fled off of the campus into a neighborhood."

He said investigators combed the neighborhood for the suspect and contacted residents with doorbell cameras to analyze.

"The individual appears to be of college age," said Mason, adding that the person of interest "blended in well with the college institution."

Brad Garrett, a retired FBI agent and an ABC News contributor, said the evidence investigators have shared so far paints a picture of a suspect who planned the shooting down to the last detail, including discarding the possible murder weapon along his escape path.

"He probably did that [because] he didn't want to be seen carrying a weapon, running through a neighborhood, or walking through a neighborhood," Garrett said.

Garrett said the discovery of the weapon is a major clue that will give investigators additional leads to track down.

"Where did it come from? It could very well be registered or purchased by this shooter. We'll have to see," Garrett said. "Was it stolen? Whatever it might be, the ATF [the federal Bureau of Alcohol, Tobacco, Firearms and Explosives] will help them immediately, and they probably already know what that is."

Garrett said the discovery of the killer's palm print can also be helpful.

"If he's ever had a full set of prints, where you print the entire hand, let's say he'd been in the military or some aspect of the government or a contractor, they may have those," Garrett said. "That's a long shot, but they may have those."

Garrett said the distance from where the shot was fired could also shed light on the identity of the gunman.

"My guess is ... a scope and a tripod would have helped him a lot for steadiness, but the real key is if he was able, and sadly did, fire one shot that killed Charlie Kirk, that's showing some proficiency because it's very difficult to have the breathing and the concentration to pull off one shot like that and that's what killed the person," Garrett said. "Does that suggest prior training? Maybe. It certainly suggests somebody who's been practicing a lot with this weapon or some weapons just like this."

Garrett said investigators are likely going to every gun range and gun shop in the area to determine if the gunman had visited them.

"The concern obviously as time goes on ... did he leave the area? If he's smart, then he did," Garrett said. "But many times, these kinds of shooters don't do that."

ABC News' Pierre Thomas and Luke Barr contributed to this report.