A 6 month-old is in the hospital with head injuries after the child's parents got into an argument, and a man with a gun came to the baby's aid.
Police say the couple argued around 11:30 p.m. Friday in the parking lot of a motel in the 16500 block of I-10 W.
They say the parents tugged the infant back and forth, and dropped the baby.
Police say a witness saw the incident and pulled out a gun, telling the parents to sit down while he called police.
The parents were arrested for child endangerment and injury to a child.
The witness had a concealed weapon permit and will not face any charges.
The infant was taken to University Hospital with head injuries.