LONDON -- British investigators say there is no initial evidence of engine failure in the police helicopter that crashed into a Glasgow pub last month.

Nine people died when the helicopter crashed through the roof of The Clutha pub on Nov. 29, including the civilian pilot and two police officers aboard the aircraft. Thirty-two people were injured, 12 seriously.

The Air Accident Investigations Branch said Monday that initial evidence indicates the helicopter struck the roof of the pub with "a high rate of descent and low/negligible forward speed."

It said preliminary examinations show that all of the helicopter's main rotor blades were attached at the time of impact but the main rotor and tail one were not rotating.

No reason was given for what could have caused that, and the investigation continues.