Daniel Castrillon-Oreggo seemed to be coming to grips with the end of his marriage.
His wife, Luz Jimenez, moved out of the couple's home in the Trillium development earlier this month and filed for divorce last week. Then the 39-year-old learned she was already seeing someone new.
On Friday, his 7-year-old son, Sebastian, made a startling statement to reassure his father: Don't worry. You're still my dad. The other guy is just my stepdad.
"I think that's what really pushed him over the edge," said Jose Guerrero, a friend of Castrillon-Oreggo's who was there during the encounter.
At some point between Friday night and Sunday evening, Castrillon-Oreggo fatally shot both of his children — Susana, 8, and Sebastian — at his home, then turned the gun on himself, Hernando Sheriff Al Nienhuis said Monday during a news conference in front of the house on Nodding Shade Drive.
Jack-o'-lanterns lined the house's front sidewalk. The rear window of a gold Suzuki sport utility vehicle parked in the driveway bore stick figure decals: mother, father and two children.
"It's very, very difficult any time you have innocent children killed," Nienhuis said. "It's even worse when they're killed by somebody who's supposed to be there to take care of them."
On Friday afternoon, Castrillon-Oreggo picked up the children from their school, Chocachatti Elementary in Spring Hill, then went to visit Jimenez at her job at an apartment rental office, Nienhuis said. The parents argued — the sheriff didn't say about what — but Castrillon-Oreggo calmed down and left with the kids for a weekend visit as planned.
Later that evening, the sheriff said, the couple spoke again, and Castrillon-Oreggo talked about moving back to his native Colombia after the divorce.
Jimenez had planned to pick up the kids Saturday to take them to a birthday party, but could not reach her husband. She came back to the house several times Sunday and called authorities when no one answered the door.
Deputies entered the house about 7:30 p.m. and found Sebastian in bed, dead from a single gunshot wound, Nienhuis said. In a bed in another room, they found Susana's body alongside her father's. Investigators believe the children were sleeping when they were shot.
Castrillon-Oreggo does not have a criminal record in Florida. Nienhuis said deputies had never been called to the house for domestic issues.
Castrillon-Oreggo left a note that Nienhuis described as typical of a disgruntled ex-husband but didn't provide additional details.
A woman who answered the door at the apartment listed as Jimenez's new address closed the door on a reporter Monday morning.
Sebastian was a second-grader and Susana was in the third grade at Chocachatti, a magnet school for the arts in Spring Hill. The Hernando County School District sent grief counselors to the school Monday morning, a district spokesman said.
Property records show Castrillon-Oreggo bought the four-bedroom house in 2006, about the same time Chris and Rebecca Cook moved in across the street. The couples' children played together.
Monday morning, Chris Cook stood in his driveway, looked up at the sky and choked back tears.
"He was always such a good dad," Cook said. "I never saw him raise his voice or be mean. That's what I'm struggling with the most. You never would have suspected he would do something like that."
Guerrero, the friend, met the family about a year ago through a youth basketball league. He said the couple met in their native Colombia and had been married for about 10 years.
But Jimenez grew distant in recent months, and Castrillon-Oreggo suspected she was having an affair, Guerrero said. On Friday, he came with the children to Guerrero's home and showed him some proof. That's when Sebastian made the comment about the stepdad, Guerrero said.
Castrillon-Oreggo left despite Guerrero's efforts to persuade him to stay. At 11:58 p.m., Guerrero said, Castrillon-Oreggo posted a comment on his wife's Facebook page, in both Spanish and English: "Thanks for replacing me so quickly. Now I can move on.''
Guerrero struggled to understand his friend's actions.
"The only thing I can think of is that he couldn't bear the idea of some other guy telling bedtime stories to his kids at night," he said. "I'd rather remember him as the guy before that."
Times staff writer Dan Sullivan and researcher Carolyn Edds contributed to this report. Tony Marrero can be reached at firstname.lastname@example.org or (352) 848-1431. Follow @tmarrerotimes on Twitter.