Authorities continue to investigate the circumstances surrounding a helicopter crash in Houston on Sunday evening that killed four people on board and sparked a massive flame within sight of homes.

The private helicopter with four people on board, including a child, either struck a cable or the tower, Houston Police Chief J. Noe Diaz said at a news conference.

A helicopter that crashed into a Houston radio tower, killing all four people aboard and starting a fire below, was on an air tour flight at the time, authorities said.