Inoperable safety lighting on a radio tower may have contributed to a helicopter crash in Houston’s Second Ward near downtown on Sunday evening.

The crash took the lives of all four people on board, including a young child.

The helicopter, which had taken off from Ellington Field moments before it crashed into the tower, was privately owned, and its destination was unknown. The National Transportation Safety Board (NTSB) said that the helicopter was operating as an air tour flight.

The identities of the four persons aboard have not yet been determined.

The red obstruction lights on the radio tower were allegedly inoperable at the time of the crash. The lighting issue was reported to the FAA on October 16. However, a white beacon at the top of the tower appeared to be flashing at the time of the crash, as seen in a security camera video.

The crash occurred just before 8 p.m. near Engelke Street and Ennis Street and caused a massive fireball in the night sky. The radio tower collapsed, spreading debris over a wide area. A fire broke out over a three-block area, but it was quickly extinguished by the Houston Fire Department.

The tower stood in an empty field, so no homes or businesses were reported damaged in the fallout from the crash and ensuing fire, and no other persons were injured. However, there were reports of damage to vehicles from falling debris, including a shattered windshield.

Houston police spokesperson Jonathan French said the department is asking anyone who finds debris to contact law enforcement.

“Any debris is considered evidence,” French said. “With daylight, more things are going to be found.”

The NTSB and the Federal Aviation Administration are leading the investigation into the crash, with assistance from the Houston Police Department. HPD is conducting a 3-D scan of the crash site, which it will then turn over to the NTSB.