Investigators said the girl's family had left her sleeping inside the van while they visited friends at an apartment complex in Lakewood and the vehicle was towed after the apartment complex manager saw that it did not have a permit to park in the lot, the Rocky Mountain News reported Thursday.

"It's never a good idea to leave a child alone in a car -- 30 seconds, 10 minutes or over an hour," Lakewood police spokesman Steve Davis said.

Davis said the tow truck crew called police after they discovered the sleeping girl while removing the van from the tow truck at an impound lot in Denver.