Newton, 23, was booked in the Santa Rita Jail, Alameda County's jail in Dublin, on suspicion of murder and is being without bail, park police said today.
Homicide investigators are still not clear about a motive in the slaying of the infant, according to park police.
Police received a call reporting a vehicle accident at about 10:30 a.m. Saturday on Arroyo Road near the Wente Vineyards, park police said.
Officers from the EBRPD Police and the California Highway Patrol responded to the scene and found a badly damaged 2013 Honda sedan abandoned on the roadway near the EBRPD Camp Arroyo facility.
The car's engine was running and there was an empty child car seat inside, park police said.
Officers searched the area, including Arroyo Park, Lake Del Valle Dam, Wente Vineyards and the Veteran's Administration Hospital, but could not locate the driver.
At about 12:30 p.m., as officers were preparing to the tow vehicle away, believing it to be a hit an run collision, a woman carrying a baby approached them, according to park police.
Officers contacted the woman, whose name has not yet been released to the public, and noticed the baby was non-responsive, police said.
The officers attempted to resuscitate the baby, but were unsuccessful. The baby, who suffered multiple stab wounds, was declared deceased by paramedics at the scene, park police said.
According to park police, the woman told the officers she had stabbed the baby and was subsequently arrested.
Alameda County Sheriff's Office Crime Lab personnel responded to the scene to assist in the investigation. A knife, believed to be the weapon in the homicide, was found at the scene, park police said.
The mother was found suffering from an apparent self-inflicted stab wound to her wrist and was treated at a nearby hospital before being released into police custody.
Park police detectives contacted the woman's family members in San Jose in an attempt to determine a motive for the fatal stabbing. Detectives have determined that the woman had a history of depression but are still working to determine a motive.
Detectives believe the woman acted alone, but park police detectives and the Alameda County District Attorney's Office are continuing to interview her to gain more information.
The deceased victim was turned over to the Alameda County coroner's bureau and a forensic examination is scheduled for later this week.