Michigan State Police are investigating whether or not faulty brakes played a role in a crash that killed two Niles sisters and critically injured another Sept. 11 in Howard Township.

Julianna Brown, 9, and Sophia True, 6, died from injuries sustained in the crash. Penelope True, 4, sustained critical injuries, but is “improving,” according to Sgt. Mike Dawson with the MSP.

The driver of the vehicle carrying the three sisters — Sarah Michael, 19, of Niles — failed to stop at a stop sign at the intersection of Leet Road and M-60 and was broadsided by a truck traveling east on M-60. Michael survived serious injuries.

Dawson said Michael told police her brakes didn’t work. Dawson said an investigation found no brake fluid in the vehicle’s master cylinder.

Dawson said police are investigating whether the master cylinder was empty before the crash or after the crash.

“We are checking to see if the brakes did fail,” Dawson said.

“So far it is proving that it may end up being the cause, but we are not yet ready to announce that it was the actual cause. We still have a little more work to do with our mechanic.”