Taxi driver killed in fiery bridge crash had flat tire

Zakim Bridge, Monday.

Massachusetts State Police now say the woman killed in a deadly crash on Zakim Bridge in Malden on Monday had a flat tire.

That was the reason she was stopped on the bridge. Debra Sarno, 54, of Chelsea was killed when a tractor trailer rear-ended her taxi.

Both vehicles caught on fire. The driver of the truck had minor injuries.

State police are now trying to figure out why the driver of the truck failed to swerve out of the way or brake.