Story highlights Authorities identify decomposed body as a missing San Diego

Gianni Belvedere, 24, was engaged to Ilona Flint, 22, who was fatally shot

Flint's body was found in a car with her fiance's brother, also fatally shot

What some speculated as a love triangle has now become a triple homicide

The Christmas Eve double killing tantalized Southern California: a 22-year-old woman and her fiance's brother were found shot, both in the head, in a car in a San Diego mall parking lot.

Then Ilona Flint's fiance went missing, prompting a monthlong search that officially ended Thursday when authorities identified a body found in a car 100 miles away in Riverside as that of Gianni Belvedere, 24.

What some first speculated as a love triangle gone wrong with two brothers has now become something more complicated -- a triple murder case in which authorities are still seeking suspects and explanations.

Belvedere's body, decomposed in his own car trunk, was identified by fingerprint, and his death was ruled a homicide, Riverside police said Thursday. San Diego police have scheduled a press conference on the case Friday.

It all began after Flint finished work at a Macy's that was open late for Christmas shoppers in Mission Valley Center Mall.

Salvatore Belvedere apparently went to pick up his future sister-in-law in the post-midnight darkness -- a gesture close friends described as a family courtesy, dismissing media speculation about a love triangle.

At 1:15 a.m. on December 24, Flint called 911 from a car reporting she had been shot, but she didn't know the vehicle's exact location, other than being near the mall.

Police found Flint dead in the car and 22-year-old Salvatore Belvedere, in the driver's seat, fighting for his life with gunshot wounds to his head and torso. He died three days later.

Gianni Belvedere was last seen at his residence at about 10 p.m. on December 23. After the double shooting, a police bulletin listed him as a missing person.

Police and the coroner in Riverside on Thursday declined to comment about their investigation into Gianni Belvedere's homicide.

"There was a lot of idiotic speculation that Gianni had something to do with the shooting or that he had possibly harmed himself, that he might have fled, that he was in a jealous rage and did this," said Andre Briones, who was such close friends with Flint that he has a tattoo of her likeness on the inside of his left forearm.

"Anyone who knows the family, anyone who knows Gianni and Ilona's relationship completely understands that there is no possible way that could have ever happened," Briones told CNN on Wednesday.

Flint had worked for a year at a vintage clothing store that Briones owned, he said.

Investigators haven't disclosed a motive in the double murders at the mall, other than they have ruled out robbery.

"In looking through the evidence at the scene, it does not appear that any sort of robbery took place during this incident," San Diego Lt. Michael Hastings said.

In the days after the shooting, Belvedere family members joined candlelight vigils and made urgent public appeals to find Gianni Belvedere. The family also appealed to their missing son and brother.

"If you hear me, please call me, call your family, we do need you right now," Antoinette Belvedere, a sister, told reporters two days after the mall shooting.

The two brothers worked at a family Italian restaurant in Lakeside, outside of San Diego, Briones said. Flint and the two brothers lived in the Belvedere family home in San Diego, Briones added.

"She was with Gianni for a very long time. They loved each other deeply. And she really cared about Sal," Briones said. "Even though she was shot ... she was still able to call 911 for herself and Sal."

Gianni Belvedere's car was discovered Friday in a fast-food parking lot in Riverside.

Neighbor Karen Regalado said she noticed the car was parked in the lot for about a week and a half, but "I never smelled an odor coming from it."

But one passer-by did notice something suspicious and called police, who found a decomposed body of a young man in the trunk.

The engaged couple were together for about seven years and met in Provo, Utah, where Flint's family lives. Flint then moved to San Diego at her fiance's invitation, Briones said.

"They were a great family," Briones said of the couple and the brother.