In the final months of his life, James "Whitey" Bulger wrote letters from prison offering his thoughts on a range of subjects.

His faltering health. His longtime girlfriend. His wish for a peaceful death.

But there was another topic that the notorious Boston crime boss returned to again and again: President Donald Trump.

In several handwritten letters shared with NBC News, Bulger expressed gushing praise for Trump, offering rave reviews of the president's foreign policy and combative relationship with the media.

"Trump is tough and fights back instead of bowing down to pressure — and caving in to press!" Bulger wrote in August 2018. "U.S. agrees with him press attacking and his reaction increases his popularity — He has my vote so far."

"History may show Trump was the man of the hour," Bulger wrote in a different letter earlier that month. "Feel China respects him and hesitant to try to bully him."

Bulger has been the subject of endless fascination, his life of crime and long flight from justice chronicled in countless newspaper articles, books and TV series. But his political views have largely gone unknown.

Until now.

The legendary gangster, who was beaten to death inside a West Virginia prison cell last fall, was an ardent Trump supporter and fan of conservative media figures such as Rush Limbaugh and Sean Hannity, according to the letters shared with NBC News.

"I get some strange mail at times — a grandmother from Kansas — hates Trump wants him 'impeached,'" Bulger wrote in one letter. "She assumes I hate him? Why Because I'm in prison?"

The missive goes on to reference the allegations that Trump paid off two women with whom he had extramarital affairs. The aging gangster wrote that he believed Trump was a changed man and would never, for instance, engage in a romantic encounter with an intern in the Oval Office.

"My bet is he's happy with present wife and settled down," Bulger says in the letter. "No way would he wind up in Oval Office with a Monica Lewinsky — That was a scandal! Same media that attacks Trump would cover up for Bill Clinton."

Bulger also railed against former special counsel Robert Mueller. An assistant U.S. attorney in Boston in the 1980s, Mueller went on to lead the FBI at a time when it was grappling with a sensational scandal involving agents protecting mob leaders like Bulger.

"Sorry to hear Trump is being boxed in by so many," Bulger wrote last August.

"Trump is experiencing what Mueller and company can orchestrate," Bulger said in a different letter from September. "[Mueller] should observe biblical saying - 'Let he who is without sin cast the first stone.'"

One month later, Bulger was dead.

The 89-year-old was fatally bludgeoned with a lock stuffed inside a sock in late October 2018. He was killed within 12 hours of his arrival at the Hazelton federal penitentiary in Bruceton Mills, W.Va., according to prison records obtained by NBC News.

No one has been charged in the killing, and federal prison officials have yet to explain why Bulger, an FBI informant, was placed in a general population unit at one of the country's most violent penitentiaries.

While behind bars, Bulger was a prodigious letter writer. In the weeks after he was sentenced to life in prison in 2013 for a raft of crimes, he began a correspondence with an unlikely person: one of the jurors who convicted him.

Janet Uhlar, a nurse who lives on Cape Cod, said the experience of sitting through Bulger's trial left her convinced that he was a murderer. But she was also troubled by the government's handling of the case, namely the deals that were cut with mobsters who provided what she found to be dubious testimony against Bulger in exchange for lenient prison sentences for serious crimes.

"I needed to hear his side of the story," Uhlar told NBC News.

Janet Uhlar, a former juror on the James "Whitey" Bulger trial, reads a letter that the Boston gangster sent her from prison. NBC News

Their correspondence got off to an uneasy start.

"No disrespect," Bulger wrote in his first letter to Uhlar in September 2013, "but I don't trust prosecutors, judges, jurors, FBI agents, CIA..."

But he was apparently won over by her skepticism of the case put on by Boston prosecutors. Bulger went on to send Uhlar more than 75 letters over the next five years.

Most of them were written in a flowing cursive that filled every inch of lined papers; a few he penned in tiny block print.

Writing from his cell, often deep into the night, Bulger mused about his mortality.

"All I want is peace and quiet for these last days and sit out on prison yard in my wheelchair," Bulger wrote in a letter written two months before his murder. "...Good friends 'lifers' went out that way under blue sky."

He ranted against Boston prosecutors and the mob turncoats who testified against him.

He furiously denied ever killing women or working as an FBI informant.

He fondly recalled his life on the outside — even with the ever-present threat of arrest or an unnatural death.

"I loved to travel and appreciated it always," Bulger wrote. "The thought — enjoy while I can can end in a flash or in prison — always there but made me appreciate each day more."

In time, he and Uhlar developed an emotional bond. After her 26-year-old son died of a drug overdose in 2014, the once-feared gangster sent letters with long passages offering words of consolation.

"I'm glad your family are there for you, Janet," he wrote in January 2015. "I'm sure Josiah would want you to understand he loved you and in desperation wanted to have a period free of pain."

"Poor Josiah suffered terribly for a long time searched for Relief and it led to this," Bulger added.

A Christmas card sent to Janet Uhlar from Whitey Bulger. Courtesy Janet Uhlar

Throughout their correspondence, he also sent Uhlar keepsakes, including a tongue-in-cheek "Christmas card" that he said was created by his niece. "She has a good sense of humor," he wrote on the back.

Bulger also shipped off to Uhlar a photo of him in prison when he was a much younger man. On the back, he documented his short-lived attempts to step away from the criminal life.

"This was my final prison picture close to graduation and have to go out in the world to compete," Bulger wrote. "1st job 1.25 an hour in a noisy paint shop — 2nd and final job union laborer 3.65 an hour — After that went back to what came naturally."