TEMECULA - The twin teenage girls in their Halloween costumes, wearing the garb of their beloved motocross, flashed vibrant smiles at the camera. They did not know - at 15, why would they even imagine - that death would come within weeks.

Narissa and Nikita Williams were the center of their mother's world, friends said Tuesday. And it was with their mother, Naomi Grangroth, that they spent their last few moments together as a family, before gunshots cut short the lives of all three.

Police are not saying who the triggerman was, but they have confirmed that the 34-year-old mother and her daughters were among the five people shot and killed Sunday in the Temecula residence of Jeffrey Blixt, who was Grangroth's boyfriend. His 17-year-old son, Matthew Blixt, also died.

Friends of Grangroth and her twin daughters said they are trying to come to grips with the deadly eruption of violence on a quiet street in a middle-class neighborhood.

"They would come into a room and take over, they had such magnetic personalities, all three of them," said friend Dana Vance, who lives in Oceanside. "People just naturally gravitated to them."

The family was tight, and their mother was grounded, Vance said.

"Naomi was a strong, independent woman who was a survivor," Vance said. "Come hell or high water, she survived. And she did everything for those girls."

Strength and independence seemed to define Grangroth.

"I think of her as a very strong, loving, determined woman who was raising two girls on her own for a long time," friend Valerie Shannon said. "She was extremely vulnerable in some ways but determined to do things without pity or help. She worked very hard to get where she was at. She didn't take short cuts."

Grangroth worked the last four years for Douglas E. Barnhart Inc., a San Diego-based general contracting firm. She started out as a secretary, and worked her way up toward a management position, coordinating and managing logistics on the job sites, a Barnhart spokeswoman said.

As it turned out, Grangroth was on the construction team that worked to build Great Oak High School, where her daughters would later attend school.

Not long ago, Grangroth - who took classes one night a week for a year - completed a course in the general contracting field to work toward advancing her career.

"It is so unreal that this has happened," said Joanna Heinrich, the Barnhart project manager who supervised Grangroth. "She showed a lot of potential and wanted to move up. She was determined to make a good life for her and her daughters."

Heinrich said Grangroth had recently begun attending church with her in Murrieta, and had successfully steered her daughters toward the church youth group after they started to get into a touch of trouble.

"They believed in God and heaven," Heinrich said. "It was a good time in all of their lives."

Heinrich said she was struck that Grangroth - who had served proudly in the Army years ago - died on Nov. 11, which was Veterans Day.

Vance said Grangroth had started to fall hard for Jeff Blixt and "just raved to me about him all the time."

Shannon said it was a slow process, and Grangroth took it slow with Blixt after meeting him in May.

"This last week, she was on cloud nine with him," Shannon said.

On Thursday, he surprised her at work with the delivery of a dozen roses.

Shannon uses words like funny, goofy and sweet to describe the man who had just won her friend's heart, the man who was teaching motocross riding tricks to the two eager twins.

For Grangroth and Blixt, bringing their kids together was a relatively new step, Shannon said.

"They solidified where they were (in their relationship), and now that they felt comfortable, they wanted to bring the kids around each other," she said.

Despite the distinct personalities of Grangroth's identical twin daughters, it was "tough to tell them apart," even though Narissa had dyed her blond hair a dark color, Shannon said.

Narissa, she said, was more of a caretaker, while Nikita tended to be more childlike and filled with wonder.

"They were so petite, just little packages of energy," Vance said. "They were unique and individual, but definitely cut from the same cloth."

The girls dabbled with dreams of competing professionally in motocross. Narissa's room was painted white with a black racing stripe; Nikita's room was pink and black, also an homage to motocross.

Friends agreed that although the two may have loved motorcycles and riding in the dirt, at heart they were teenage girls - kids who continually experimented with their hair color and loved to play with makeup.

As freshmen at Great Oak High School last year, both girls landed in the strength and conditioning class taught by Richard Tucker, who said the two "always had a smile and could never stay unhappy for very long."

"They were a kick in the pants," Tucker said. "You know, there's times they would see how much they could stretch you. It was never done with malice. Call them on it and they fall in line. It was never mean. The girls are good girls."

They may have found themselves raising a little too much Cain recently, friends said. But it was "kid trouble, kinda like Huck Finn trouble," Tucker said.

By Tuesday afternoon, a small makeshift memorial began growing on the front porch of Blixt's Temeku Hills home. One teenage girl in a babydoll dress walked up slowly.

The girl, who declined to share her name, sat down and sobbed. She had come to say goodbye to the twin girls she knew from classes, friends she said were like sisters to her and who "were always laughing."

"I miss them so much," the grieving girl cried loudly as she stood on the porch. "They weren't at school today. They were supposed to sit next to me."

A 7-year-old blond boy soon walked up, clutching a bouquet of flowers. The child's father, who blinked back tears, said he and his son had befriended Jeff Blixt when he moved in down the street from them. The man said his young son had just been going through a stack of motorcycle patches that the elder Blixt had recently given him.

Among the gifts on the front porch were five stuffed bears tied to a balloon bouquet. One, with a card for Jeff Blixt, came with a toy motorcycle. The bear with a card for Matthew Blixt sat with toy racing cars.

"We've known you since you were a precious little loving boy. May God's loving mercy surround you," read the card.

- Contact staff writer Teri Figueroa at (760) 631-6624 or tfigueroa@californian.com.