Woodfox and Wallace claimed they were targeted because of their activism as Black Panthers.
Wallace, who was serving an armed robbery sentence at the time of Miller's death, and Woodfox "were threatening the status quo," Trenticosta said.
King was transferred to Angola just weeks after the guard was killed. Even so, he was investigated as a possible "conspirator" and put into solitary confinement alongside Wallace and Woodfox, according to the documentary "In the Land of the Free." He was never convicted in connection with Miller's death.
King was convicted in 1973 of killing a fellow inmate. His conviction was overturned in 2001, and he was freed.
Diagnosed with cancer this summer
Wallace proclaimed his innocence in Miller's death in appeals.
"Mr. Wallace has fought his unconstitutional conviction for decades and is supported by four alibi witnesses who place him in another part of the prison when the tragic murder occurred," his lawyers said Tuesday.
According to his lawyers, Wallace -- after losing between 40 and 50 pounds -- was found this summer to have terminal liver cancer.
Chemotherapy treatment has not been effective and was suspended, according to Trenticosta, one of the attorneys for Wallace and Woodfox. He said the cancer should have been treated much earlier.
Wallace and Woodfox, who remains in prison with appeals pending in his case, "endured very restrictive conditions, including periods of 23-hour cell confinement," according to Amnesty International USA.
"Tragically, this step toward justice has come as Herman is dying from cancer with only days or hours left to live. No ruling can erase the cruel, inhuman and degrading prison conditions he endured for more than 41 years," Amnesty said.
The human rights organization said it knows of only one other person in the United States who has been held for longer under such conditions.
The American Civil Liberties Union of Louisiana, asked authorities not to appeal the ruling that freed Wallace.
"We hope that they will see reason instead, and allow Herman Wallace the chance to spend his final days outside of the confinement he has endured for more than 40 years," the group said in a statement.
Trenticosta said he last saw Wallace a few weeks ago.
"There is no anger with Mr. Wallace," the lawyer said. "He is the strongest person I have had the great opportunity to represent. He is about positive thinking."