Arson investigation underway after explosion damages parked cars in Humboldt Park

CHICAGO (CBS)-- An arson investigation is underway after an explosion in Humboldt Park.

Police said an explosion, in the 3300 block of West Crystal Avenue just before 3:30 a.m. damaged four parked vehicles.

A resident recorded video on her cell phone as she walked outside to see cars on fire on her street.  

No injuries were reported.