TOOELE — Over a five hour period, a 16-year-old Grantsville boy waited for each member of his family to come home so he could shoot and kill them, prosecutors say.

“This happened over a five-hour period, piece by piece by piece by piece. This wasn’t one horrific act all occurring in one minute,” said Tooele County Attorney Scott Broadhead.

He said the killings do not appear to be a case of “I snapped.”

On Wednesday, Colin Jeffery “CJ” Haynie, 16, was formally charged as an adult in 3rd District Court with four counts of aggravated murder, one count of attempted aggravated murder, and five counts of discharge of a firearm. All of the charges are first-degree felonies.

If he is convicted, Broadhead said the maximum penalty the teen could face is life in prison without the possibility of parole. Because Haynie is a juvenile, he is not eligible for the death penalty.

In disturbing charging documents filed late Wednesday afternoon, prosecutors outlined how Haynie stayed home from school on Jan. 17 and waited for each member of his family to come home that day. Colin Haynie, the father and husband of the victims, told police that CJ Haynie told him after the shootings that “his intention was to kill everyone in the house except himself,” charging documents state.

The biggest question yet to be answered is why.

“We have no answer at this point as to what his motive or mental state was,” Broadhead said. “He has declined to speak to police.

“We all have the same questions. Why? We don’t know. Hopefully that’ll be developed through time.”

The county attorney said he could not comment yet on whether investigators believe drugs or alcohol may have been factors.

The killings began about 1 p.m. Friday when CJ Haynie’s mother, Consuelo Alejandra Haynie, 52, and 12-year-old sister Milan returned home from school. He shot them multiple times in their heads, necks and upper bodies, according to charging documents.

About 2 p.m., Alexis Haynie, 15, arrived home. Alexis was shot multiple times in the head and upper body, according to Broadhead.

About 5:15 p.m. Matthew Haynie, 14, was shot once in the head after arriving at home, the charges state.

Broadhead said it appeared each family member was shot “fairly soon” after arriving at home.

An hour after Matthew was killed, CJ’s father, Colin Haynie, arrived home and was shot in the leg, the charges state. There was then a struggle over the gun, during which the elder Haynie was injured after he was hit on the head with an unknown object.

The father said he told his son that his mother would be sad if he killed him, the charges state. “He said the defendant told him that his mother and other siblings were already dead.”

The father was able to get the handgun away from his son, who then apparently went with him to the hospital without further incident.

Broadhead said Wednesday that he doesn’t know why CJ Haynie went from wanting to kill his family to seemingly going to the hospital willingly with his father and without issue. He said the elder Haynie, as of Wednesday, had still not spoken with prosecutors and that he and his oldest son were keeping their privacy while “trying to wrap their heads around this horrific event.”

It was shortly after Colin Haynie was shot and took the gun away from his son that a neighbor happened to stop by the house to drop something off, unaware of the tragic events that had taken place, according to Broadhead. Colin Haynie had the neighbor drive him and his son to the hospital.

It was while they were heading to the hospital that CJ Haynie told his neighbor he’d killed his family, prompting the neighbor to call 911, according to Broadhead. He did not know Wednesday why the father didn’t call 911 from his house or if he had verified that his family was dead before leaving.

When police arrived at the hospital, they said CJ Haynie was calm. But Broadhead said he has not cooperated with police since his arrest.

CJ Haynie’s first court appearance is scheduled for Monday afternoon. Broadhead said the investigation is ongoing and police were still examining electronic devices such as laptops and phones hoping to find a possible motive.

Funeral services for the four deceased members of the family will be held Friday at noon at the Grantsville Stake Center, 550 E. Durfee St. The services will be preceded by a viewing at 10 a.m. Interment will follow at the Grantsville City Cemetery.

Alejandra Haynie was raised in Chihuahua, Mexico, according to the family’s obituary posted by Didericksen Memorial, a mortuary based in Grantsville.

“She was a loving mother to her children and loved to prepare delicious meals and desserts. She also loved to garden and care for her fruit trees. She was always willing to help out and serve people in the ward and the community,” the obituary states.

Each of the deceased children was born in Bountiful.

Alexis Haynie was a freshman at Grantsville High School where she was the goalkeeper for her junior varsity soccer team. She was also “an accomplished artist and loved to play the piano. Other interests included ‘The Lord of The Rings’ and playing with her siblings and friends,” according to her obituary.

Matthew Haynie, an eighth grader at Excelsior Junior High, enjoyed soccer, wrestling, playing chess and “anything to do with ‘Star Wars’ and gaining the ‘high ground.’”

Milan Haynie was in the seventh grade at Excelsior Junior High. In addition to playing soccer and volleyball, she enjoyed “creating art with her sister, taking a specialized interest in superheroes,” and leaving “loving and encouraging notes,” the obituary states.

The family is survived by their father and husband, Colin Haynie, and older brother Danny Haynie, a Utah Valley University student. The Haynie family has lived in Grantsville since 2010.