ROCK HILL -- At some point after 11:30 p.m. Sunday, investigators say either the father or the mother of Jairo, Denise and Denia Meza used a knife to slash their throats.
No screams were heard by neighbors. The children's bodies were carefully laid out on two beds in the master bedroom. A combustible liquid was splashed around the room and ignited.
This is what investigators say happened at 4053 Crestview Drive late Sunday or early Monday, based on physical evidence and more than a dozen interviews with neighbors, friends and family members.
Neighbors were awakened by a 3 a.m. "commotion followed by a bang, like soft thunder," which was probably a buildup of heat that blew out the front window. A pilot light to a hot water heater may have also caused a small explosion.
Authorities said the children's parents -- Denis Meza, 39, and Marbely Meza, 30 -- died from smoke inhalation and burns in the fire. Their bodies were found on the floor in the bedroom with the children. No one had attempted to flee the fire zone. Marbely Meza had knife wounds that could have incapacitated her, but authorities are not yet able to tell which parent killed the children.
Because the bodies were so badly burned, as of late Tuesday, only one person had been positively identified -- Denis Meza, through his fingerprints. York County authorities had taken his prints earlier this summer when he was charged with sexually abusing his 14-year-old daughter, Denia, since she was 10. He was to appear in court Monday.
"There's no two ways about it: These little children were murdered, and that's a terrible crime," said York County Sheriff Bruce Bryant. "We further believe that the murderer died in the fire."
Bryant said evidence was still being processed and it was too early to determine exactly what happened.
"At this point we have no reason to believe it is not the Meza family; everything seems to point in that direction, but with the bodies so badly burned you just can't say until they can complete the DNA tests or dental records," Bryant said. "What we have is five dead people. Is it a straight murder or a murder-suicide? We just can't say at this point."
York County Coroner Doug McKown confirmed the children -- believed to be Jairo, 5; Denise, 8; and Denia, 14 -- died from "massive blood loss from having their throats cut." A knife stained with a dark substance was found near their bodies. He said the woman had a knife slash on her wrist, which could be a "defensive wound."
McKown said it would be several days before DNA tests would be completed to positively identify the other four bodies.
The Meza family is from Nicaragua; they have lived in the Charlotte area since the early '90s. Friends say Denis Meza, a heavy-set landscaper, underwent a transformation in recent years -- one that is at odds with his behavior in recent weeks.
Noradino Montes, a friend of the family who lives in Rock Hill, said he found out about the deaths Monday night after returning from Mexico.
He said Meza had changed since they met about 12 years ago. Back then, Meza wasn't religious, Montes said. He would drink a little and occasionally curse.
"When he got to this religion, he changed," Montes said. "He stopped saying bad words; he stopped drinking." He began dressing better, too, Montes said.
In the mid '90s, Meza took a trip to Nicaragua and came back with his wife and oldest daughter.
The family was involved in a Spanish-speaking congregation of Jehovah's Witnesses, friends said. Montes said the Mezas hosted Bible studies in their former Fort Mill home on Thursdays.
Montes said Meza worked weekdays and gave all his free time to the church.
Montes said he didn't know Meza's wife well. He said he had visited the couple in their Rock Hill home only twice, but "every time I saw them they were kind to each other."