People reported hearing a loud crack before a massive branch, estimated to weigh several hundred pounds, came tumbling down from an old oak tree, authorities said.

CALABASAS PARK, Calif. (CNN) - An 8-year-old California boy was killed Wednesday after a heavy tree branch fell on him at a Calabasas park. It happened during a summer camp in the park, as a group was gathering under a large oak tree at the end of the day.

An 8-year-old boy was struck and killed by a tree branch that fell while he was attending a summer camp at King Gillette Ranch in Calabasas on Wednesday afternoon, July 9, authorities said. Authorities responded just after 2:50 p.m. to the ranch in the Santa Monica Mountains. Camp staffers were giving aid to several people.