Seconds after killing a 21-year-old father during a suspected home-invasion robbery on Friday, two suspects fired a bullet into the head of the man's 7-month-old son who was seated in a car seat, police said this weekend as they released new details on the case.

Investigators initially reported that the father, Sean Paul Aquitania, was killed inside a home after an attempted robbery and that his infant son, Sean Paul Aquitania Jr., was accidentally caught in the crossfire. But a more thorough investigation throughout the weekend determined that the son had been murdered execution-style in the car seat of his dad's Chevrolet Malibu.

"We are angered as law enforcement officers and disturbed as human beings that anyone could commit such an unconscionable act against an innocent child," said sheriff's spokesman Sgt. Tim Curran.

Authorities are still searching for the suspects, Curran said.

Aquitania — who had tattoos of his baby's hand and footprint on his forearms — drove to a home on Country Greens Court shortly before 2 p.m. Friday to visit friends. He left the infant in the car and went to the front door. Two young men answered, and two other men ran up and forced their way inside, Curran said.

A melee erupted, and Aquitania received at least two bullets in the upper body. The two suspects ran away, stopping to shoot the baby. No one else was injured, Curran said.

A 24-year-old man inside the house ran to his car and drove to get help, Curran said, and a 21-year-old man ran out of the house, scooped the baby out of the car and went door to door looking for help.

A school bus driver saw the 21-year-old man and the baby, opened the doors and held the dying infant, Curran said. The baby was taken to UC Davis Medical Center, where he was pronounced dead about 5:15 p.m.