David Kendall, best known as the lawyer who defended President Clinton during his impeachment, cut his legal teeth representing murderers like John Spenkelink and Gary Gilmore. Eventually it was his argument at the Supreme Court in Coker v. Georgia that resulted in the death penalty for rape being declared unconstitutional.

In a rare example of the corporate and the criminal coming together, Kendall now is defending contracting behemoth Bechtel Corporation in a Massachusetts-based investigation that could result in manslaughter charges against the company.

On July 10, 2006, a bolt failure in the new tunnel leading from downtown Boston to Logan Airport sent a chunk of concrete flying into a car, where 38-year-old Milena Del Valle was fatally crushed.

Then-governor Mitt Romney ordered a review, and sources say Boston legal authorities may charge Bechtel in the death.

Kendall won’t comment on the case but has been seen at Logan and National airports on weekends going to and from Boston. Kendall watchers say that for decades he has worked pro bono on death-penalty cases. But no one is going to send Bechtel to the electric chair in this case.

Still, says one friend familiar with the years of free legal advice Kendall has given to save the lives of criminals: “At least this time he can get paid for all his expertise in this field. That isn’t usually the case.”