Massachusetts Governor Mitt Romney says his office has begun taking legal steps to remove the head of the state's Turnpike Authority following a deadly accident in a Boston tunnel.

Romney said Tuesday it is time for change and he has instructed his legal counsel to find a way to remove Matt Amorello from his post.

Also on Tuesday, the state attorney general Tom Reilly launched a criminal probe into the incident.

The developments come one day after a three-ton concrete panel fell from a ceiling that is part of the so-called "Big Dig" tunnel system late Monday, killing a woman in a car.

Inspectors are working to ensure that 100 similar ceiling panels pose no danger. The Big Dig has become a central route through Boston.

The biggest public works project in U.S. history, the 15-year-long, $14-billion undertaking has been plagued by cost over-runs and water leaks.

Some information for this report was provided by AP.