In surveillance footage, Daniel Mitchell is seen driving up to a parking spot at 141 Sunset Ave. in Suisun City and opening the door to the back seat of his car. When he drives away, a car seat is seen left on the ground.
People at nearby J's Barber Shop first noticed the carrier and saw the baby inside after his father drove away.
Police arrested Mitchell after he was involved in a hit-and-run in Fairfield, where officers later found him.
When tests at the North Bay Medical Center revealed that the 16-day-old had an unspecified condition, he was flown to a hospital for further treatment.
Mitchell was treated for injuries he sustained in the collision at the North Bay Medical Center.
Police arrested Mitchell at the hospital on probable cause for child endangerment and abandonment, committing a felony while on bail and misdemeanor possession of suspected cocaine.
In a separate incident on June 27, police arrested Mitchell for his alleged connection to a burglary.
The baby's mother, who is married to Mitchell, has spoken with police and is not a suspect.