A Bell 407 GX aircraft hovers overhead as the crew takes aerial photos of 1,000 residents walking in formation at Liangjiang Square in Yunyang county, Southwest China's Chongqing municipality on Sept 12, 2015. [Photo/CFP]

A Bell 407 GX helicopter from Chongqing General Aviation Co. Ltd. crashed while taking aerial photos in Southwest China's Chongqing municipality on Sunday, killing four people onboard, local authorities said.

The crash happened at around 1 pm as the aircraft lost contact with ground control after departing from Wanzhou district and heading to Liangping county in Chongqing municipality on Sunday.

Rescuers found the helicopter's debris and all four victims at around 6:30 pm in Hucao Village of Liangping County.

The cause of the crash is under investigation.