Joe Biden believes the death penalty "must stop" at the federal level, except for those guilty of terrorism and mass murder motivated by hate, the White House said.

Trump often called for expanding the federal death penalty — including for those who kill police officers, those convicted of drug and human trafficking, and migrants who kill U.S. citizens.

Tsarnaev was convicted of all 30 charges against him, including conspiracy and use of a weapon of mass destruction and the killing of Massachusetts Institute of Technology Police Officer Sean Collier during the getaway attempt. Prosecutors said the brothers carried out the attack to punish the U.S. for wars in Muslim countries.

President Joe Biden is commuting the sentences of 37 of the 40 people on federal death row, converting their punishments to life imprisonment mere weeks before President-elect Donald Trump, an outspoken proponent of expanding capital punishment,

Marvin Gabrion was convicted and sentenced to die more than two decades ago for killing a woman who had accused him of rape.

Biden preserved the death sentences of three mass murderers but commuted the sentences of 37 other federal death row inmates to life in prison.

Recent polling shows support for the death penalty at a five-decade low, and half of the population thinks the death penalty is applied unfairly.