His 11-year-old brother already had escaped to a neighbor's house and was hysterical, talking with a 911 dispatcher just before 8 p.m.

Neighbors said when Tonja Marie Nash walked outside her home at 1183 W. 680 South to look for her sons, she didn't get far. A man she had met online and joined in Utah, Keith Lamont Morton, walked up behind her and fired into her back.

Morton aimed the shotgun at Nash's head and pulled the trigger a second time before kicking her motionless body and walking back inside, said Loretta Zapata, who watched in horror with her 7-year-old daughter from their house across the street.

Nash was later pronounced dead at Timpanogos Regional Medical Center.

Zapata said she began flicking her daughter's bedroom light off and on in an attempt to deter Morton from shooting the boys, who had heard the gunshots and returned to find their mother lying face down in a pool of blood.

As she and other neighbors urged the frantic children away, Zapata said the 8-year-old cried, ''My mom! I need to be with my mom!''

The older boy yelled, ''That bastard! He shot my mother in the back. I'm going to kill the son of a bitch,'' said neighbor Becky Coley.

Within minutes, the small home next to a Utah Valley State College student parking lot was surrounded by officers who provided cover for paramedics as they carried Nash away. The 40-year-old woman was still breathing as they loaded her into an ambulance.

Officers coaxed Morton into surrendering and leaving the home about 20 minutes later.

The boys' father, Daniel Nash, traveled from Arizona early Tuesday to take custody of them - and tell them their mother is gone. Tonja Nash's 15-year-old daughter lives with Daniel Nash.

"The kids are with me," he told The Salt Lake Tribune. "We're safe."

Morton, 50, was booked in the Utah County jail, where he was being held on a $750,000 cash-only bond on suspicion of murder as of Tuesday afternoon. According to a probable cause statement filed at the jail, Morton called his mother, Faye Cassingham of Orem, to tell her he had just shot Nash. When Morton was told of Nash's death, he said he did not mean to kill her, the statement said.

Morton was prosecuted last year for attempting to strangle Nash on Thanksgiving Day.

Jeff Morton, Keith Morton's younger brother, made a statement late Tuesday on behalf of the Morton family.

"We want to extend our deepest sympathy to the Nash family, especially to the children," he said. "Keith has been struggling with mental health issues for a long time. But that in no way justifies his actions. There are many victims in this tragedy, and our prayers go out to all."

Nash, whom friends and family called "Toni," met Morton online, according to relatives of the couple, and moved to Orem from Tucson, Ariz., about a year ago to be with him. Her sons joined her in Utah this summer.

Mary Ann Estrada, Nash's mother, said her daughter was an avid backgammon player on the Internet and had met men on the Web. About three years ago, Estrada said in a telephone interview, Nash flew to New Zealand to visit a man she met online.

"She didn't deserve this," said Estrada. "She's too trusting."

She described her daughter as ''a very effusive person'' with a good sense of humor.

"She would walk through glass to help someone," Estrada said.

Nash was working at a Gold's Gym in Orem, her family said. A few weeks ago, she called her ex-mother-in-law, Muriel Nash, in Tucson to say she might move back and work at the Gold's Gym there.

"She sounded very happy, and I thought everything was OK," said Muriel Nash.

But police reports show Morton assaulted her shortly after she moved to Utah.

On Thanksgiving Day in 2005, Orem police responded to a 911 call hang-up, Orem Department of Public Safety spokesman Doug Edwards said. Morton had tried to strangle Nash, then disabled the phone when she called for help.

Morton was charged with misdemeanor assault and another misdemeanor for interrupting the 911 call. He entered pleas in abeyance and was ordered to attend domestic-violence counseling. Counseling service reports filed with the court say Morton was making "good progress" and had "shared his feelings about his aggressive behavior with the group and has invited his girlfriend to attend group with him."

Morton, who was born and raised in Provo, worked at a brick manufacturer and currently is employed by a die-cast manufacturer in Orem, according to his ex-wife, Dorothy Morton.

She said her ex-husband never was violent toward her or the two children they have together. The couple split about a year ago but remain amicable, she said.

Dorothy Morton said she also was friendly with Nash.

Nash ''was a fun gal,'' she said. ''I really enjoyed the time I spent with her.''

Dorothy Morton lives only four blocks away from where the killing occurred, and she did not hear the shotgun blasts Monday night.

"We heard the sirens, but had no idea it happened until it hit the news," she said.

Tonja Nash's children were living in northern Arizona with their father until this summer, when their father brought the kids to Orem and viewed the house, Muriel Nash said. He thought the living arrangement was acceptable, and the boys remained with their mother.

At Vineyard Elementary School, where Nash's sons are students, a moment of silence was held Tuesday.

lrosetta@sltrib.com

ncarlisle@sltrib.com