It was a case that puzzled investigators.
Who would want to shoot a mother and her 4-year-old daughter just feet from their Long Beach home this summer?
Detectives spent more than three months scouring evidence and interviewing witnesses who may have seen something.
“An investigation of this magnitude that began with no leads is very difficult to work,” Long Beach Police Chief Robert Luna said. “Sometimes a case like this can take years to solve.”
On Monday, Luna said detectives had arrested Brandon Colbert, 22, of Tulsa, Okla. After identifying him as the main suspect in the Aug. 6 killings, police discovered he was in Los Angeles County jail after being picked up three weeks later on suspicion of driving a stolen vehicle.
Luna said investigators plan to present their case to prosecutors Tuesday to determine whether to file charges against Colbert in the slayings of Carina Mancera and her daughter, Jennabel Anaya.
“Today their family and our community can find some comfort and the knowledge that a person believed to be responsible for their deaths is in custody," Luna said.
But even after the arrest, a key question remains unanswered: Why would anyone kill the mother and daughter?
The motive for the shooting remains unknown, Luna said.
“We haven’t ruled out the possibility that others may be involved in this horrific crime,” Luna said, adding that a $40,000 reward has been offered in the shootings.
Investigators learned that Colbert boarded a Greyhound bus Aug. 3 in Tulsa and arrived in Los Angeles the next day, the police chief said.
Police are now looking to retrace Colbert’s last steps and are trying to determine if he left California after the shooting, only to return later, or stayed in the area until his arrest in the stolen car case.
The mother and daughter were returning from grocery shopping around 10:20 p.m. when a gunman emerged at the intersection of Locust Avenue and 9th Street, police said.
The gunman opened fire on Mancera and her daughter, then fired one shot at Luis Anaya, Mancera’s boyfriend, who is the father of Jennabel. Anaya was not hurt, but Mancera, 26, died at the scene. Jennabel died at a hospital a short time later.
In September, police released surveillance footage that showed a man they wanted to question inside a convenience store near the shooting scene. He was also spotted in footage riding a Metro Blue Line train carrying luggage shortly after the shootings.
Police said Colbert is the same person seen in the footage.
It is unclear how detectives linked the person in the videos to the shooting. Police have said that Anaya, the surviving boyfriend, did not recognize the man in the videos.
Luna said police had DNA from the gunman they retrieved at the scene of the killings, but he did not elaborate. Detectives submitted the DNA to an offender database but nothing came up at first.
On Aug. 27, Los Angeles police officers arrested Colbert on the stolen car case and his DNA was taken to be added to offender databases. On Oct. 31, the Los Angeles County Sheriff’s Department’s crime lab confirmed a match, Luna said.
Luna said he is hoping someone who knows Colbert or may have seen him comes forward to help police.
Long Beach Mayor Robert Garcia praised detectives for their work on the case.
“We’re of course thinking and praying during this time for the family of both Carina and Jennabel,” he said. “It’s been a difficult few months, but our thoughts and prayers are with them and we know that hopefully today will bring them some level of peace and ability to process this in their own way.”
Times staff writers Joseph Serna and James Queally contributed to this article.
4:30 p.m.: This article has been rewritten and new details added about how police say they linked Colbert to the killings.
1:45 p.m.: This article was updated with Long Beach police announcing that Brandon Colbert, 22, of Oklahoma was arrested in the killings.
This article was originally published at 11:45 a.m.