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Investigators say a bloody attack on a rural East Texas family's home may have resulted from family opposition to a daughter's boyfriend.

Rains County Sheriff department confirmed Sunday a 16-year-old girl is one of four suspects being held for the violent murders of her mother and two brothers.

The girl, whose name is being withheld due to her age, is the girlfriend of one of the suspects, investigators revealed. Neighbors told MyFOXDFW.com that the girl's parents, Terry and Penny Caffey, were trying to break up the couple.

"I knew that Terry and Penny didn't like him and were going to make her split up with him," the unidentified neighbor told the station.

The teen was found by police early Sunday hiding at the home of one of the suspects, although it was not clear from the police account which of them she was dating or where she has been hiding.

The four suspects, which include the unidentified teen, 19-year-old Charlie James Wilkinson, 18-year-old Bobbi Gale Johnson and Charles Allen Wade, 20, went before the Justice of the Peace and were formally charged Sunday morning with three counts of capital murder each, police said. All remained in Rains County Jail with bonds set at $1.5 million.

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The scene of the attack was about 20 acres of pine-canopied, remote woodland on a narrow gravel road with just two other homes between the small East Texas towns of Emory and Alba. That is about 60 miles northeast of Dallas in Rains County, the second-smallest county in Texas.

Penny Caffey, 37, was killed along with her two sons, Tyler Caffey, 8, and Mathew Caffey 13, according to police. All had been shot and stabbed multiple times. Terry Caffey was in critical but stable condition Sunday in East Texas Medical Center in Tyler, where he was being treated for a gunshot wound to the head.

Despite his wound, the father was able to crawl about 300 yards to a neighbor's house to seek help. Meanwhile, flames consumed the Caffeys' home with the bodies of Mrs. Caffey and their two sons inside.

The sheriff said authorities could not determine whether gunshots or the fire caused the deaths of Penny, Tyler, 8, and Mathew, 13, saying, "The bodies have been so badly burned."

Autopsies have been ordered.

Carl Johnson, a family friend, said he drove to the secluded road early Saturday after being told of the fire.

Johnson described the family as musicians, the boys playing guitars and harmonica and the mother piano at church. He said he'd often tell the teenage daughter that he wanted her to sing at his funeral.

"I just thought the whole world of the family," said Johnson, 75. "They were good Christian people. (The father) was like a son of my own."

Harold Read, who lives about a mile away, said he was awakened by what he thought was thunder around 4 a.m., the time when authorities were first called to the house.

"All you read about out here are ticky-tacky crimes in the local paper," said Read, 67. "I never lock my doors. This is a quiet place."

By late Saturday, firefighters sifted through the ash and singed metal that was all that remained from the house. A wooden sign tacked to a tree in the family's dirt driveway read "Joshua 24:15," and a burned van was parked near where the home once stood.

Joshua 24:15, a verse from the Old Testament, reads in part, "But as for me and my household, we will serve the LORD."

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FOX News' Harris Faulkner and the Associated Press contributed to this report.