A tow-truck driver unknowingly hauled away a car with a seven-year-old asleep inside, before returning the vehicle minutes later and speeding away, police said.

The panicked parents of the missing boy watched the driver hurriedly unhook their car and take off as they met with authorities late Monday, according to a Dallas police report. A possible kidnapping investigation at the apartment complex had already begun.

Fidel Retana Jr, 23, was pulled over a short time later and arrested on child-endangerment charges. But police said Tuesday they expect to drop the charges.

"It appeared that he did not intend to take the child," Dallas police Sgt Brenda Nichols said.

David Traylor, Retana's attorney, said his client noticed the boy only when he stopped to ensure that the car was hooked up properly. The car had been parked in a fire lane while the boy's mother ran upstairs to her apartment.

Traylor said Retana left the second time in a hurry because he knew the parents were there and were probably angry.

"He tried to do everything he could to get the kid back quickly," Traylor said.

Authorities said the boy's mother was crying and vomiting outside when they arrived. The boy was still asleep when the car was returned.

"I hate the way towing people run the business," said Sergio Zuniga, the boy's father.