A 49-year-old Puna man was arrested on suspicion of a triple murder on Hawaii island early Friday morning when police found him driving a car with blood dripping from the trunk and the body of a woman inside. The bodies of two children were found in the couple’s home.

Police arrested John Ali Hoffman on suspicion of three counts of second-degree murder, one count of first-degree murder and a firearm offense. He is being held at the Hilo police cellblock while detectives continue their investigation. He was not charged Friday.

Hoffman’s sister Sumayah Hodges identified the victims as her brother’s wife, Aracey, and their children, Clara Mae “C.J.” and John IV. She said the girl was about 8 years old and the boy, the girl’s brother, was two or three years younger.

“This is a huge shock,” Hodges said from her home in St. Louis. “Nobody would have ever suspected this.”

Police were called to the family’s home on Moku Street in the Leilani Estates subdivision because of a disturbance at about 1:30 a.m. Friday.

Arriving officers spotted a man leaving the house and driving off without the headlights on. Officers stopped the car and saw a firearm on the front seat. They arrested Hoffman and noticed what appeared to be blood dripping from the trunk. When they opened it, they found a woman’s body inside. The children’s bodies were inside the family’s house.

Hodges described her brother as a troubled man who had major setbacks while living in Hawaii, including the loss of his business and home. He apparently believed he was being wronged and targeted by judges, the mayor and some “heavy hitters” with political connections, she said.

She said Hoffman also contended with immigration problems for his wife, who was from El Salvador.

Hodges said Hoffman’s troubled state of mind was evident in a recent phone conversation.

“He told me that he had to turn himself in, him and the family,” Hodges said by phone from their hometown of St. Louis. “I said, ‘The kids, too? What police officer would take these kids?’ But he didn’t want to elaborate. But yesterday he was emotional.”

Hodges said, “He loved those kids. We just don’t understand it.”

Police have not identified the victims.

Criminal Investigations Division Capt. Robert Wagner said one child’s body was found in a bedroom and the other in an open area inside the house. Police declined to release information on how they were killed.

Identification of the children could pose a problem because they have likely not been fingerprinted.

“How do you ID a juvenile with these set of circumstances? The people who were caring for them, one expired and the other is in jail,” Wagner said. Police will check for dental records and might need to use DNA testing, he said.

There is no indication Hoffman and the woman were married, but they were together for a while, he said.

Hoffman wrote a long and rambling post on Facebook the night before the slayings. Some of his post pertained to setbacks tied to landownership.

In 2012 Hoffman was sued for failure to complete payment for property he bought, court records show. Two years later the court granted judgment in favor of the sellers, and he was forced to vacate the property. He continued to file documents including a complaint for relief alleging criminal fraud, deceit and unfair enrichment.

Hodges said Hoffman at one time operated a sanitation business on Hawaii island, but he eventually lost his business and was unable to land a job.

Hoffman’s neighbors were shocked by the news of the slayings.

Dale and Lana Sclafani, who live nearby on Moku Street, said they would see Hoffman during their afternoon walks and wave to him as he drove into the driveway. They said they loved to hear the sound of the children playing in the yard, especially because the street does not have many young residents.

“We walk the dogs to the end of the road (Moku Street). The kids sounded like they were having so much fun,” Lana Sclafani said Friday. “When they first moved in (about a year ago), we welcomed them to the neighborhood.”

She recalled when Hoffman asked them for recommendations of fun activities in the area. Although the couple, who have lived in Leilani Estates for 15 years, did not speak with Hoffman frequently, she said “they seemed like a normal family.”

“This is a real tragedy. It’s going to affect a lot of people in the neighborhood,” she said. “It’s just really awful.”

Police officers cordoned off a section of Moku Street on Friday where the bright red house was barely visible from the road. Several residents slowly drove past the area and wondered when the crime scene tape would be removed.

At a nearby community park on Moku Street where children and families were playing and walking dogs Friday afternoon, resident Dorothy Stadnyk said she and her family had researched the area before moving to the subdivision a few years ago. At the most recent neighborhood security watch meeting, she said officials reported no crimes in the area.

“This is a wonderful neighborhood, and it’s a shock that this happened,” Stadnyk said. She said she did not know Hoffman, but would see the woman walking down Moku Street while the two kids rode their bikes.

Anyone with information about the case is asked to call police at 935-3311 or contact Detective Scott ­Amaral at 961-2276 or email scott.amaral@hawaiicounty.gov.

Anonymous tips may be made to CrimeStoppers at 961-8300.