Forbes is serving a life sentence with no chance of parole for killing Aurora teen Kenia Monge and savagely attacking Lydia Tillman from Fort Collins, who he physically and sexually assaulted, setting her apartment on fire to cover up the crime.
Kerry Humphrey, 24, admitted to lying about Forbes' whereabouts the night Kenia went missing and cut a deal with prosecutors.
She was sentenced Wednesday for attempt to influence a public servant, false reporting to authorities, and perjury in the second degree.
The judge sentenced her to 60 days in county jail and four years of supervised probation. She was also ordered to complete 2,000 hours of community service and seek mental-health counseling.
"They should've thrown the book at her. I really do believe that," Tony Lee, said. "I have to accept the judgment of the court. Even though I'm unhappy with the sentence, I believe in the system."
Humphrey spoke only to 9NEWS Crime and Justice Reporter Anastasiya Bolton. She told Bolton she lied to police to protect the man she trusted and loved at the time.
HOW THEY MET
"We actually met through some mutual friends," Humphrey said. "He actually came very highly recommended by all of them.
"We had some sort of instant attraction," said Humphrey. "He had a tendency to kind of draw you into conversation. He would find a way to kind of relate it to what you've been through, some story that you told. In a way, I let my guard down and felt understood and started trusting him."
They met in late December 2010, before Forbes' met Monge in April 2011 and attacked Tillman in July of that year.
In December and early 2011, they were just Travis and Kerry, and they were in love.
"[He was] very generous," Humphrey said. "He was always about random acts of kindness, if you will, and he showed those things to me. I remember vividly when one day during that winter, we were walking down the street ,and the street was all lit up. It was snowing with these big fat flakes of snow, we were just walking back to my apartment. [We] happened to pass by some older woman who seemed down on her luck, and he whisked off his scarf and gave it to her. Without even thinking about it. I was very taken aback [and thought] 'Wow, this guy seems like a very good guy.'"
Over the holidays, Humphrey went home to New Mexico, and gushed about her new boyfriend to her family. Forbes stayed in Denver.
Humphrey was in the middle of her bachelor's degree for business management. She says she helped Forbes with his business, and they made plans together.
"He came to me he was looking for advice so I was helping him in certain ways in developing his business," she said. "We had made all these future plans developing this business, I thought they were going really well."
Forbes made granola bars and later used that bakery to store Monge's body in a cooler.
KENIA MONGE'S MURDER
But on April 1, 2011, all Monge's family knew is that she didn't come home from a night out.
Forbes told Monge's family and police he gave the 19-year-old a ride that night. He said she was drunk and he dropped her off at a Conoco on Speer Boulevard. Humphrey said she heard the same story.
"I remember looking into his eyes, and they seemed like he was in such pain and so worried about this girl. He kept reiterating. There was another guy. She left with somebody else. I feel so terrible. It should've been me that drove her home, not somebody else. I know she's missing," Humphrey said Forbes told her.
"He says that 'I'm so worried, I'm the last person who saw her.' He asked me 'If anybody asks, you can you just tell them I stayed at your place that night.' And I said yes."
So Humphrey lied to Denver Police more than once and eventually got arrested for it.
"Maybe it was too bold of me to jump so quickly to the defense of Travis, but up until that time, I had no reason not to believe him," Humphrey told 9NEWS. "I couldn't believe it. I couldn't believe it. When he sat next to me and told me those things, I couldn't even imagine what the repercussions of those would be."
By her second police interview later in April, she and Forbes had broken up. She still stuck to her story at first, but when police showed her cell phone records, Humphrey admitted that Forbes didn't stay with her, the night Monge disappeared.
Since the mid-April 2011 break up, Humphrey heard from Forbes only once, when he called to ask for a friend's number. Humphrey asked him why he left town after Monge's disappearance, but Forbes wouldn't say.
The next time she heard about Forbes was five months later, when her father called her to say Forbes had led police to Monge's body, which he buried under a cottonwood tree near Keenesburg, about 40 miles from Denver.
"After the initial shock wore off, I was horrified at what happened," Humphrey said. "Every time I think about either Kenia or Lydia, my heart just aches because I could've never imagined the not knowing, especially with Kenia what happened to her and then finally knowing she's never coming home. I can't even imagine," Humphrey said with tears filling her eyes.
"Are you sorry you lied on his behalf?," Bolton asked.
"Absolutely," Humphrey said.
"I was never trying to cover up a murder. I just didn't know what was going on. I just thought I was helping a man that I trusted."
Lydia Tillman didn't want to comment on the Wednesday sentencing.