Jail records indicate Schaffer Grindstaff, 29, was released Monday night, but the reasoning was not clear.
He was arrested after his son, Cameron Flores, was found unresponsive at Melville J. Courson Park in Palmdale last week. Investigators said the boy's father made some inconsistent statements when they interviewed him.
Father's inconsistent statements led to arrest in Palmdale child death, investigators say
At the time, Grindstaff told deputies his son was suffering from a medical emergency. He was later arrested on suspicion of accessory to conceal a crime and child endangerment.
The circumstances surrounding the child's death remain a mystery. An official cause has not been released from the medical examiner's office.
Detectives, meanwhile, are looking to interview the child's mother.