ST PETERSBURG (Florida) - THIEVES left an 11-month-old boy on a stranger's doorstep on Monday after stealing his parents' car from outside their home with him still in the back seat, police said.

Kara Lane, 24, told the St Petersburg Times she left her son in his car seat while she went inside to get her two daughters. When she returned, a man was in the driver's seat, backing out.

'My baby is in the back seat!' she screamed over and over. Her boyfriend chased after the car but couldn't catch it.

Strangers who live about 2km away called police soon after to report that the baby had been left on their doorstep. He was safely returned to his parents.

The car was abandoned about 3km from where it was stolen, said Bill Proffitt, spokesman for the St Petersburg Police.

Authorities said they were questioning two people but still searching for the man who drove the car away. They'd gotten a call about three suspicious men in the area and found another stolen car dumped nearby.

In an unrelated incident elsewhere in Florida, authorities in Deltona said they arrested three people after a van was carjacked with a 3-year-old boy inside. Police said they spotted the van and the thieves abandoned it. The boy was not hurt. -- AP