TAMPA — On Sunday morning, a father and his two boys set out on a rolling adventure.

Pedro Aguerreberry pedaled a bicycle, pulling Bennett, 3, in a trailer, while Lucas, 8, rode his own bike. They wore helmets in case of a spill, and a swath of grass separated the bike path from cars that rumbled along New Tampa Boulevard.

In one of those cars, police say, a mentally disturbed man was about to change this family forever.

The man was Mikese Morse, who Tampa police said walked into a substation 12 days earlier rambling that he might hurt someone. The 30-year-old was taken into protective custody, officials said, but released days later. Then on Sunday, police said, he spotted the family just before noon as he drove west in a Dodge sedan.

Morse didn't know the Agurreberrys, police said, but he spun the Dodge around, crossed a lane of traffic, tore across the grass and intentionally crashed into the tiny convoy.

Pedro Aguerreberry, 42, was pronounced dead at a local hospital a short time after the crash. The younger boy was treated for a broken leg, and the older one had minor injuries.

Morse didn't stop. He fled, police say. But, within hours, he was behind bars on charges that include premeditated first-degree murder and leaving the scene of a crash with death.

Tampa police Chief Brian Dugan said an account from a witness who saw Morse make the U-turn indicates that he ran over the family on purpose. Investigators were still working Monday to understand why.

Morse admitted to the attack, Dugan said at a news conference, but didn't offer a clear explanation for his motive. "What type of person would purposely run over a family that was just bicycling down a bike path?" Dugan said.

Some clues came from the police department's own files.

• • •

Less than two weeks ago, on June 12, Morse walked into the Tampa Police Department substation on 30th Street, north of Busch Boulevard.

He told an officer in the lobby that he "did something really bad," according to a report. But he wouldn't say what it was. Morse spoke of "being attacked by energy projections." He rambled about conspiracies.

"He continued on not making any logical sense and then advised I should not let him out of the police station or he may hurt someone," the officer wrote.

Morse was taken into protective custody under Florida's Baker Act, but was released after a week.

On Monday morning, his parents, Michael and Khadeeja Morse, addressed a television news crew in front of their home, not far from the crash scene. They said their son — once a national-class track and field athlete — had been released after spending a week at Gracepoint, a mental health facility.

The parents asked Gracepoint not to release him because he had not been stabilized, the father said. A spokeswoman for Gracepoint said she could not discuss the case because of medical privacy laws.

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"We have been trying for a long time to get help for our son," Khadeeja Morse told WTSP-Ch. 10. "And the system not only failed us. It failed him. And it failed that family."

"We begged," Michael Morse said. "We did not want this to happen to anybody. We didn't know that he would do anything like this. We just knew that he needed more help. And, we have tried for years to get him help."

• • •

Videos and other posts on Morse's Instagram page — some posted near or after the time of the crash — show closeup images of a man unraveling, fixated on what he claimed to be the devil's power over him.

"I still will kill every single one of y'all on that motherf-----'s head right now," Morse said in a video posted Sunday. He appears to be walking along the edge of a wooded area while recording with his phone. "This universe can end. I do not care," he said. "You see these energies changing inside of me and stuff and trying to change perspective..."

Then, just before the video ended, Morse said: "I don't ever help a man, I'm finna' (fixing to) kill somebody tonight right now."

After the collision, Morse drove east in the maroon 2008 Dodge Avenger toward Bruce B. Downs Boulevard, Dugan said.

Meanwhile, the Aguerreberry boys "essentially watched their father die," the chief said.

Patrol officers found Morse's car in the Pebble Creek area of New Tampa. Plastic was taped to the front windshield to conceal the damage, police said.

He was located about two blocks away at his parents' home on the 9500 block of Pebble Glen Avenue. Police said he lived there. He was taken to the Police Department's downtown headquarters, where he was arrested about 9:45 p.m. Sunday. He remained in the Hillsborough County jail without bail Monday.

His arrest was a dramatic turn for a man who had distinguished himself in earlier years as a high school and college athlete, and an aspiring Olympian.

He was a long jumper at Freedom High School and a running back on the football field. He earned track and field accolades for both the University of South Florida and the University of Miami. He was a three-time U.S. Olympic Trials qualifier and two-time finalist in 2008 and 2016.

He had no Florida arrest record, only minor traffic infractions.

Police have found no sign of past contact between Morse and the Aguerreberrys.

• • •

Catherine Lavender, who lives down the street from the family, said Pedro Aguerreberry greeted her when she moved into her townhouse three months ago.

"He actually came over and he welcomed me to the community," she said. "He said if I ever needed anything to please let him know."

She said she often saw him spending time with his sons, washing the family car or riding bicycles in the neighborhood.

Aguerreberry had worked with Citi for about 20 years and on two continents, according to his LinkedIn page.

He met his future wife at the company, where she was a trainer in the Citi gym, said Juan Carlos Pinto, who worked with the husband for 15 years

Pinto called his friend charismatic and family-oriented. He often participated in community service projects. A couple of weeks before his death, he helped clean up a causeway. He was active in the homeowner's association in his neighborhood.

In one image on his wife's Facebook page, which shows a younger Bennett in the hands of his parents, a wide smile crosses the father's face.

On Sunday, Lavender was walking her dog and saw a woman knocking frantically at the family's door.

The woman asked her if she had a phone number for Meghan Aguerreberry. She said something terrible had happened. "They were just genuinely great people," Lavender said. "I can't imagine anyone wanting to hurt them or do anything like this."

Times staff writers Paul Guzzo and Bre Bradham and senior news researchers John Martin and Caryn Baird contributed to this report. Contact Tony Marrero at tmarrero@tampabay.com or (813) 226-3374. Follow @tmarrerotimes.