Big Island police yesterday charged a 27-year-old man with assault and other counts after he allegedly threw baseball-size rocks Sunday at vehicles in Hilo, seriously injuring a 3-year-old boy.

Patrick Luk of Hilo was charged with first-degree assault, 17 counts of first-degree criminal property damage and resisting arrest.

Eight drivers filed complaints about a man throwing rocks at their vehicles for no apparent reason on Puainako Street near the Kilauea Avenue intersection. The rocks struck the bodies of some vehicles and windows of others.

In one case, a rock shattered a vehicle's side window and hit a 3-year-old boy in the face, leading to serious injuries, including a laceration, fracture and brain injury. The boy was flown by air ambulance to The Queen's Medical Center on O'ahu, where he was in stable condition yesterday.

Luk was being held at the Hilo cellblock in lieu of $85,500 bail.