Prominent death penalty lawyer Judy Clarke is joining the team representing the suspect in the Boston Marathon bombings.

The appointment of Clarke, based in San Diego, Calif., was approved Monday by U.S. Magistrate Judge Marianne Bowler.

Bowler denied a request from Dzhokhar Tsarnaev's public defender to appoint a second death penalty lawyer. Bowler says Tsarnaev's lawyers could renew their motion to appoint another death penalty expert if Tsarnaev is indicted.

The 19-year-old Tsarnaev has been charged with using a weapon of mass destruction during the April 15 marathon. Three people were killed and more than 260 injured when two bombs exploded near the finish line.

Clarke's clients have included Unabomber Ted Kaczynski; Susan Smith, who drowned her two children; and most recently Tucson, Ariz., shooter Jared Loughner. All received life sentences instead of the death penalty.