A man jailed for rape and murder and whose story was documented in the Netflix series Making A Murderer will not be eligible for a pardon.
Brendan Dassey was 16 when he confessed that he had joined his uncle, Steve Avery, in the rape and murder of photographer Teresa Halbach before burning her body in a bonfire in 2005.
His lawyers argued the confession was made under pressure while being interrogated by detectives and his supporters have called for him to be released.
In a letter to Dassey's lawyers, Wisconsin governor Tony Evers said he will not consider a pardon request from the 30-year-old.
Dassey, who along with his uncle is serving a life sentence, filed the request in October but it does not meet the criteria for a pardon consideration.
Authorities said they had made the decision because Dassey has not completed his prison sentence and he is required to register as a sex offender.
Dassey's supporters have been calling for him to be freed but ran out of options after the US Supreme Court last year refused to hear his latest appeal.
Mr Evers has also made it a policy not to consider requests to commute prison sentences.
Dassey submitted a handwritten note to Evers asking for the pardon and wrote: "I am writing to ask for a pardon because I am innocent and want to go home."
He listed things he enjoys including Pokemon and hamburgers and drew a pair of hearts with the word "hugs" in one and "love" in the other.
Dassey's lawyers, Laura Nirider and Steven Drizin, said they were disappointed the pardon request had been rejected without a review.
In a statement they said: "We will continue to work, respectfully but relentlessly, towards the day when this governor recognises in Brendan Dassey the gentle, cheerful, and kind human being whom we have known for 12 years."
"A good teacher never forgets his most vulnerable students; a good governor never forgets his most vulnerable citizens."
The lawyers said they had spoken to Dassey on Friday and that "he is not giving up hope, and neither are we".
The pardon request claimed Dassey was the victim of a "uniquely and profoundly flawed legal process" and that seeking clemency from the governor is "one of the last remaining legal options" available.
Dassey's lawyers say he is intellectually impaired and was manipulated by experienced police officers into accepting their story of how the murder happened. They want his confession thrown out and a new trial.
The US Supreme Court has said he could request another trial if a judge agrees there is new evidence that warrants it.
During Dassey's trial, video of his confession to investigators played a central role.
Police had no physical evidence linking Dassey to the crimes and he testified that his confession was "made up".
However, a jury convicted him and he will not be eligible for parole until 2048.