Northern California suspect in homicides of 4 children, 2 women charged with murder

A Northern California man suspected of killing four children and two women has been charged with murder in one of the deaths.

The Stanislaus County district attorney's office on Thursday charged 30-year-old Martin Martinez with murder and child endangerment in the October death of his girlfriend's 2-year-old boy.

Martinez remained free until his arrest Sunday while the Modesto Police Department investigated.

The toddler died of head injuries suffered in fall while in Martinez' care. Martinez told police the injuries were caused by an accident.

Martinez is also suspected of the Saturday killing of his girlfriend, their 6-month-old daughter, his girlfriend's 6-year-old daughter, his mother and an unidentified 5-year-old girl.

Martinez remains jailed in Modesto, and it's unclear whether he has retained a lawyer who could comment on the case.