A woman and her four young children were killed in their central Oklahoma apartment, and authorities were looking to arrest the mother's 25-year-old boyfriend on murder charges Tuesday.

An officer went to the apartment to check on the welfare of the occupants and found the five bodies shortly after 4 p.m. Monday, said Jessica Brown, a spokeswoman for the Oklahoma State Bureau of Investigation. The children ranged in age from 3 to 7.

Brown said at an afternoon news conference that the five were not shot and that a weapon was "not necessarily used." She said more details wouldn't be released until Wednesday or later.

Cherokee Ballard, a spokeswoman for the medical examiner, would confirm only that the deaths were homicides.

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Authorities were searching for Joshua Steven Durcho of El Reno, who was charged late Tuesday in Canadian County with five counts of first-degree murder, said Assistant District Attorney Paul Hesse. A warrant has been issued for his arrest, Brown said.

Officers also were looking for the woman's missing vehicle, a 1989 white Ford Thunderbird.

Durcho's image was captured on surveillance video at a truck stop in Clinton, about 60 miles west of the crime scene, where he purchased a soft drink about 9:30 p.m. Monday, Brown said.

"We have many sightings of him so far all across the state," she said.

Brown said no motive is known for the killings but added, "I know they had their ups and downs in their relationship."

Prison records show Durcho was convicted of car theft as a juvenile and was sentenced to four years in prison in 2003 for unlawful possession of marijuana. He was released in February 2007, records show.

"He has been in and out of jail most of his adult life," Brown said.

The victims were identified as Summer Garas, 25, her daughters Kirsten Rust, 7; Autumn Rust, 6; and Evynn Garas, 3; and a son, Teagin Rust, 4.

Summer Garas was a student at nearby Redlands Community College, where she was studying to be a legal assistant, school officials confirmed.

"I'm just numb, just not knowing what to think," said Crystal Franklin, the children's grandmother and Garas' former mother-in-law. "The kids were just wonderful."

Court records show that Summer Garas and her ex-husband Jason Garas were divorced on Dec. 10.

Franklin said Summer Garas rarely locked her door and helped neighbors when they were in need.

"Summer never met an enemy," she said. "She didn't have an enemy, just loved everybody."

The slayings took place in a tidy apartment complex, with two-story buildings, surrounded by a white picket fence in El Reno, a suburb about 25 miles west of Oklahoma City.

"That was wrong, there is nothing that can justify killing a mother and four kids," said James Franklin, Crystal Franklin's husband. "Just turn yourself in.

"I have to deal with this the rest of my life. I can't see my grandkids," he said. "I loved all of them and they loved me."

Brandy Higgins, whose mother lives in the same apartment building where the five were killed, said her mother heard a loud noise before police arrived.

"All I know, my mom heard a loud boom, and I get a phone call," Higgins said. Other neighbors also said they heard a loud noise, Franklin said.

On the front porch of the apartment where the killings took place there were several children's bicycles and toys, including a rideable plastic dump truck.

Crystal Franklin said Teagin was fond of monster trucks and had planned to go with his grandparents to a truck show in Oklahoma City.

"They were just full of life, a joy to be around," she said.

Higgins' children were friends with Garas' children, and Higgins' mother had been close with the family. Higgins said she hopes whoever did the crime suffers for his actions.

"I hope it eats him alive," she said. "Them babies won't experience life."