LONG BEACH (CNS) - Criminal proceedings were reinstated today after an Oklahoma man was found mentally competent to stand trial for the shotgun killings of a woman and her 4-year-old daughter who were returning home from grocery shopping in Long Beach last year.

Brandon Ivan Colbert Jr., 23, of Tulsa, spent time in a state mental hospital after he was found mentally incompetent May 30 and criminal proceedings against him were suspended.

Colbert is charged with the Aug. 6, 2016 killings of Carina Mancera, 26, and her daughter, Jennabel Anaya, who were shot near Ninth Street and Locust Avenue. He is also accused of trying to kill the child's father, Luis Anaya, who escaped injury.

The murder charges include the special circumstance allegations of murder while lying in wait and multiple murders. Prosecutors have opted not to seek the death penalty against Colbert.

Police have not determined a motive for the killings.

At a hearing in March in which he was ordered to stand trial, Colbert said he believes the two victims are still alive and that he's being set up by police, whom he claimed staged the killings, the Long Beach Press-Telegram reported.

Prosecutors allege that Colbert hid behind a sign and opened fire on the family with a shotgun. Surveillance footage captured at least part of the shooting, according to testimony during the preliminary hearing.

Police said he was booked last November in connection with the killings after DNA evidence linked him to the crime.

Colbert had been in custody since Aug. 27, 2016, when he was arrested by Los Angeles police on suspicion of driving a stolen vehicle and a DNA swab was obtained from him.

Luis Anaya told investigators that a man walked up to his longtime girlfriend and their daughter and suddenly -- without provocation -- opened fire, then ran off. He said he did not recognize the man, nor did anyone else in the neighborhood.

The gunman also fired at Anaya, but missed, according to police.

Colbert -- who is acting as his own attorney -- is due back Oct. 17 in a Long Beach courtroom, with his trial tentatively set to begin Dec. 5.