Other forms: amnestied; amnesties
Amnesty means an official pardon, often for a large group of people. When political prisoners receive amnesty, all legal records of their convictions are officially eliminated.
Amnesty sounds a little like "amnesia," and that's because in its more specific sense amnesty means "forgetting." The government will essentially forget about any crimes that may have been committed. As part of a truce, amnesty can be granted to opposition forces, and if an incarcerated person gets amnesty, they're set free.