GRANTSVILLE, Utah (AP) — As investigators try to unravel why a teenage boy shot and killed four of his relatives, loved ones prepared to mourn the family at a funeral this week in a small Utah town.

Police said the boy surrendered peacefully after killing a 52-year-old woman and three of her kids and wounding the children's father last Friday in Grantsville, a town of 11,000 about 35 miles (55 kilometers) west of Salt Lake City. But he has since refused to speak with detectives trying to piece together a possible motive.

Authorities have declined to release the suspect's age, name or relation to the victims until formal charges are filed.

A funeral for Consuelo Alejandra Haynie, 52; her daughters Alexis, 15, and Maylan, 14; and son Mathew, 14, has been scheduled for noon Friday at a regional worship building for The Church of Jesus Christ of Latter-day Saints in Grantsville, a mortuary said Tuesday in an online post.

Hundreds of people gathered Monday night for a candlelight vigil for the family where some expressed compassion for the suspect.

“On so many levels, this is so tragic for our community," family friend Diane Passey said, according to the Deseret News. “Not just for the mother and the four lives lost but also for the poor young man who was in such a dark place.”

Police responded to a call of shots fired inside the family's home Friday night and found the four bodies, police Sgt. Rhonda Fields said.

The shooter and the father of the family were gone, she said. Authorities later discovered that a person who arrived at the house after the shooting drove the teen and the man to a hospital, Fields said. Officers arrested the boy there.

The father of the family was released from the hospital after being treated for a gunshot wound and was talking with investigators.

They were trying to put together a timeline to help figure out what happened, Fields said. Authorities said they had not been called to the house in the past.

“The biggest question everybody has is 'why,' and while we may not be directly able to answer that, we hope to be able to gather some information to be able to help people in future to be able to prevent something like this or offer support to those who may need it," Fields said.

Relatives of the victims asked for privacy during the investigation. Patty Deakin-Daley, a realtor who started a fundraising campaign to help cover the victims' funeral expenses, said she had been in touch with a brother and a son of the injured father, 50-year-old Colin Haynie said.

A statement from the Haynie family that Deakin-Daley read at the vigil expressed both deep sorrow and appreciation for the outpouring of love.

“It is our hope and prayer that at this difficult time, we focus on the positive moments that we have shared together. We are finding for ourselves that as we mourn, it is beneficial — if not necessary — to cheer our spirits with good memories, and even a bit of laughter," it said.

The boy was being held at a youth detention facility on suspicion of four counts of aggravated murder, one count of attempted aggravated murder and multiple firearms charges.

Officials said he is the only suspect. The person who drove them to the hospital was not involved in shooting, Fields said.

It appears to be the largest mass shooting in Utah since 2007, when a shotgun-wielding gunman killed five people and himself at a Salt Lake City mall.