Santa Rosa police were struggling Friday to piece together details about Thursday night's fatal shooting of a 19-year-old man in southwest Santa Rosa.

It remained unclear how the victim, identified as Eduardo Caballero, even ended up at the Marble Street home where he later died in the absence of anyone who resided there, police Sgt. David Linscomb said.

A teen was in the house at the time and reported hearing the fatal shot from another room, Linscomb said. But neither he nor a third teen who was there when officers arrived had seen the shooter or seemed to know who was responsible, Linscomb said.

Detectives had not completely ruled out suicide or an accident death, though they believed Caballero likely was slain, Linscomb said.

"There's a lot of ifs, and, like I said in the press release, we're treating it like a homicide because that's what it's looking like to us," he said.

Caballero, a Santa Rosa resident, was known to local police, but it was unclear where he had been living at the time of his death, Linscomb said. Police said Caballero was a gang member, but it remained unclear whether that played a role in his death.

At their arrival at 8:40 p.m. Thursday, police found Caballero on the floor, bleeding from a gunshot wound to the head. He died there a short time later.

An autopsy is scheduled for Monday, coroner's Sgt. Greg Stashyn said.

Neither of the other teens, ages 16 and 17, who were with Caballero when police arrived were residents at the address, Linscomb said. But police believed they and the victim knew someone in the family that lives there, possibly a teenage son whose whereabouts weren't known, he said.

A woman contacted at the house on Friday with one of her twin 17-year-old sons said the violence has left them struggling with the disturbing mystery about what went on in their absence on Friday.

She said neither she nor her son recognized the name of the victim nor had any idea why he and the others were in their house. She denied reports of past gang activity associated with her family.

But she acknowledged that one of her twin sons had recently run away from a juvenile offender camp to which he had been sent last fall in what she said was a marijuana-related case. She said he may have friends who are associated with gangs but did not believe he was a member.

The woman, who declined to give her name, said she doesn't know where the missing son is now but said she did not believe he was in the area or had any connection with the shooting.

"If that kid (the victim) -#8212; whoever it was -#8212; had gang ties, I don't know anything about it," she said.

Several neighbors described the woman as a friendly, longtime resident of the neat subdivision south of Cook Middle School, southwest of the intersection of Stony Point and Sebastopol roads. She has two older children who no longer live at home.

They said her son who remained in the home appeared to be an upstanding young man who attended school and avoided trouble.

But there had been troubling incidents in the past at the house, some of which they believed were linked to the other twin, that have marred the neighborhood's otherwise generally quiet atmosphere.

There also has been recent violence elsewhere in the neighborhood, including the Nov. 17 stabbing of an 18-year-old man who was walking near Marble Street and Gardner Avenue when he was attacked by several people who reportedly asked his gang affiliation.

The mother-and-son occupants of the house also acknowledged that two of three stabbing victims who had been at an out-of-control party up the street last May had come to their house before being rushed to local hospitals.

"If there's a shooting, you know, that's too close for comfort," one neighbor said Friday, declining -#8212; like all of those interviewed in the neighborhood -#8212; to be named publicly.

The resident of the house where the shooting occurred and her son agreed to answer questions from a reporter just after they had returned home for the first time since Thursday's bloodshed and the ensuing, all-night investigation.

The woman said she had been at work when the shooting happened. Her son said he was at a school basketball game with his dad, having left home at 6:30 p.m. Other than the 30 minutes he was home beforehand, he said, no one had been home all day.

But one neighbor said he saw two young men walk toward the house and apparently inside earlier in the day. Another remembered noticing a dark car pull up in front of her house just around the corner and seeing five or six youths open the doors and exit simultaneously, all or most of them pulling up hoods and walking quickly toward the house about two hours before the shooting.

Linscomb said the missing son had a history of associating with gang members, and said there was a history of gang members coming to the house. He said police have not ruled out that the twin might have been in the neighborhood without his mother knowing.

"As far as we know from this investigation, it's possible that he was at the house and that these people that were at the house are associates of his," Linscomb said.

If it's determined to be a homicide, Thursday's shooting would be the third in Santa Rosa in less than three weeks.

A 22-year-old homeless man, Nicholas Bloom, was found stabbed to death behind the downtown Santa Rosa library on Christmas Eve. Another transient has been charged in the case.

Six days later, early on the morning of Dec. 31, Damien Wadell Toney Jr., 23, was fatally shot after a dispute at a party at a Piner Road apartment complex. A 15-year-old teen has been charged in that case and is to be prosecuted as an adult.

You can reach Staff Writer Mary Callahan at 521-5249 or mary.callahan@pressdemocrat.com.