A 19-year-old mother is under arrest on child abuse and aggravated DUI charges after police say she left her five-week-old baby strapped in a car seat on top of her 2000 Ford Focus and drove off.

The child is said to be in good condition and now in custody of Arizona Child Protective Services.

At about 1 a.m. Saturday, Phoenix police officers got calls from the 45th Avenue and Cholla area, just south of Cactus Road, that a baby was in a car seat in the middle of a road.

Phoenix Fire Department officials found the baby and took him to a local hospital. He was "perfectly OK," said Officer James Holmes, spokesman for Phoenix police.

Holmes said the mother, Catalina Clouser, had apparently been smoking marijuana late Friday night at a nearby park with her boyfriend. At about 11 p.m. they left the park to buy some beer. The boyfriend was arrested on aggravated DUI charges while on the way, Holmes said.

An upset Clouser then reportedly went to a friend's house where, she admitted, she smoked more marijuana, Holmes said. By midnight, Clouser left the house with the baby asleep in the car seat.

She realized the baby was missing when she reached home. That's when Clouser called her friends and asked them to trace the route she had taken. The friends ran into the officers who had already found the baby. Clouser arrived there shortly thereafter and was arrested, Holmes said.