(CNN) -- It wasn't enough that jurors at the federal trial of James "Whitey" Bulger had to sort out sometimes graphic testimony from 72 witnesses and the 32 criminal counts against the reputed Boston mobster.
They had to gauge the believability of unsavory criminals who had taken plea deals.
"You weren't sure what you could believe or what you couldn't believe," juror Janet Uhlar said Tuesday.
Testimony revealing deep-seated corruption in the FBI and government during Bulger's heyday left Uhlar disgusted with a justice system she called "tainted," even now.
"Almost every witness that came through for the prosecution, I just had this feeling like it's tainted. It's tainted," said Uhlar, a pediatric nurse and the author of several books on the American Revolution.
She spoke to CNN in her first interview since the jury on Monday found Bulger guilty of 31 counts.
The juror spoke succinctly when asked to describe her gut thoughts about some of the trial's key witnesses.
Bulger hit man John Martorano:
Bulger crime partner Stephen Flemmi:
"I can't cuss on TV."
Mob enforcer Kevin Weeks:
"Scary. Still scary. ..."
Disgraced FBI supervisor John Morris:
"There's no words. There's no words, absolutely disgusting. I felt like a traitor."
Still, Uhlar and her 11 fellow jurors found Bulger guilty of extortion, money laundering, drug dealing and weapons possession. They found he was responsible for 11 of 19 murders under a wide-reaching racketeering charge.
Bulger, who turns 84 in two weeks, faces a maximum sentence of up to life, plus 30 consecutive years in prison.
Uhlar called Bulger an "old, tired man" and said she wasn't convinced he was a government informant, as prosecutors had alleged.
Known as Juror Number 12, Uhlar told CNN the government "enticed" many Bulger associates to testify by giving them "extremely outrageous deals."
"When you think if Martorano killed 20 people in cold blood and basically got a slap on the hand in less than a year for each of those murders. I mean, for me, that was huge. That was huge."
Prosecuting attorney Fred Wyshak, in closing arguments, defended the government's plea deals with gangsters, three of whom together implicated Bulger in the 19 murders and various acts of extortion.
"The government didn't choose them, Bulger chose them," Wyshak said.
"The only thing worse than making a deal with (former hit man) John Martorano would have been not making a deal with John Martorano."
Wyshak said the government "held its nose and made the deal."
Uhlar criticized Morris, who testified about leaking confidential information that led to the murders of Bulger crime associate Brian Halloran and Michael Donahue, an innocent truck driver caught in the crossfire.
"Morris walks away having been actually involved in two murders -- Halloran and Donahue -- and gets promotions and retires at a nice old age with a full pension," Uhlar said.
Like it did with many key witnesses, the government cut a deal with Morris. In exchange for his testimony, Morris would not be charged as an accessory to murder and would get to keep his pension.
In court, he apologized to Donahue's family for leaking information that eventually made its way to the reputed South Boston crime boss and cost Donahue his life.
Bulger declined to take the stand in his defense, telling the judge, outside the jury's presence, that his trial was "a sham" and claiming he had been given immunity for his crimes by a corrupt prosecutor. Bulger never specified what he gave in exchange for that alleged immunity.
The judge barred Bulger's defense team from bringing it up at trial, saying there is never any immunity for murder.
Uhlar said that aside from the testimony of Bulger's cronies, she and the other jurors could find no supporting evidence in several murders that they ruled "not proved." She said the jurors believed it was not Bulger, but his crime partner Flemmi, who killed Deborah Hussey and Debra Davis, both 26.
"Whether Bulger was present with Debbie Davis, that was something we couldn't agree on," said Uhlar. "With Hussey, we also felt that Flemmi killed her. Now, was Bulger present or not? He had been involved and present at the other two murders in that same house, so it was hard to remove him from that. So yeah, but we felt pretty strongly that Flemmi was the one that killed the two women."
His defense lawyer said Bulger was "very pleased" by both the trial and its outcome.
"It was important to him that the government corruption be exposed, and important to him that people see first hand the deals that the government was able to make with certain people," attorney Jay Carney told reporters Monday.
Prosecutors offered up extortion victim after extortion victim to show Bulger conspired to collect "rent" from operating criminals in South Boston.
Uhlar said she is convinced Bulger was guilty. But she is still troubled by what she calls a "free pass" for those called by the prosecution in their pursuit of Bulger.
"It was just pretty sickening to sit there and hear some of the testimony and the corruption with government and that -- at one point, I think one of the prosecuting attorneys talking about money laundering. And they were explaining once the tainted money goes into anything, every bit of money that now comes from that is now tainted. And I felt that way about the trial itself in a very real sense."
Uhlar said she is haunted by the vivid descriptions of killing after killing.
"It's still with me," the juror said. "It's hard to believe human beings can do this to other human beings. ... I told my sisters, I'm different, I'm never going to be the same. Really, I can't be the same after this."
CNN's Ross Levitt, Kristina Sgueglia and Laura Batchelor contributed to this report.