When death penalty expert Judy Clarke joined the defense team for the Unabomber, Ted Kaczynski, she spent months trying to establish a rapport so she could convince him to accept a plea deal that would spare him capital punishment.

Though she and his other lawyers angered Kaczynski when they sought to introduce evidence of his mental illness, he eventually pleaded guilty in 1998 and received a life sentence.

Defense attorney Judy Clarke speaks at the Fidler Institute on Criminal Justice at Loyalo Law School in Los Angeles, California, on April 26. Provided by Reuters

"I think she has a real gift", David Kaczynski, his brother said on Tuesday, a day after Clarke was assigned to the defense team for Boston Marathon bombing suspect Dzhokhar Tsarnaev. "Even if it's the smallest sliver of common ground, Judy's going to be able to find that. There's no doubt in my mind that Judy saw my brother's humanity despite the terrible things he'd done."

Tsarnaev, 19, is accused of setting off explosives on April 15 near the finish line with his older brother, Tamerlan, killing 3 and injuring 264. He was arrested on April 19 after a massive manhunt that left his brother dead following a police shootout.

Tsarnaev faces charges of using a weapon of mass destruction and malicious destruction of property with an explosive device, both of which can carry the death penalty when they cause the death of others. He has not yet entered a plea. US authorities have not said whether they will seek capital punishment.

In court papers asking a judge to appoint Clarke as a public defender, one of Tsarnaev's lawyers, Miriam Conrad, cited a federal law giving defendants in potential capital cases a right to an attorney with experience handling death penalty cases.

Over nearly two decades of representing infamous defendants in capital cases, Clarke, who opposes the death penalty, has built a national reputation for avoiding executions for her clients.

In addition to Kaczynski, Clarke defended Eric Rudolph, the 1996 Atlanta Olympics bomber, who was spared the death penalty.

Reuters