Produced by Chris Young Ritzen
(CBS) SAN CLEMENTE, Calif. - "That day and what happened that day is gonna be with me until the day I die. It's something I carry on my conscience every day," John Needham explained. "I just can't believe that this is where my life is right now. When I look back when I was younger, I never see myself at 26 years old being called a murderer."
"I was trained to kill. ...I come home. I can't adjust to regular civilian lifestyle," Needham continued. "I spun out of control. I needed help."
"Unfortunately with the way I was trained, you know to react to threats is to neutralize threats. ...Even with someone I love."
In July of 2009, John Needham was out on bail... but far from a free man.
"I feel like a tagged animal," he said looking down at his ankle bracelet. "This is a constant reminder of what has happened and what is true reality no matter how much I try to hide from it or try and escape from it."
Needham was awaiting trial for a crime he found difficult to comprehend - killing a woman he says he loved.
"You know she was absolutely precious to me. She still is," he said.
Jacqwelyn Villagomez was 19 when she died and had only known John Needham for a few months. She'd been a track star in high school - and was hoping to break into modeling and acting.
Sarah and Spencer Savino were so close to Jacque they considered themselves sisters. At odds with her own family, Jacque lived with the Savinos for a year when she was 17.
"She had a really vivacious personality," Sarah Savino told "48 Hours Mystery" correspondent Troy Roberts. "They call it the Jacque glow. Like she just had this glow about her. From her big bright teeth and her smile."
"What did you learn about her life before she came into yours?" Roberts asked.
"I learned that her mom had passed away when she was very young. She lived with a grandmother and her brother," Sarah Savino replied.
"Wasn't a very happy home. Just didn't feel loved. ...I don't think she had a sense of real belonging and what a real family life was like."
"And she found that with your family?"
"I believe that she did."
But when Villagomez graduated from high school and set off on her own, she struggled on and off with drugs. She had talent, but drifted from job to job.
"She had her issues with...her mom dying very young of AIDS. She's had her drug addictions," John Needham explained. "She had her issues and I had my issues. I just got back from Iraq and we were both broken people. And we kind of mended well. We kinda helped each other."
It was Iraq that broke John Needham. After serving more than a year, he came home shattered physically and emotionally. He'd been diagnosed with post-traumatic stress disorder or PTSD.
"When people asked how John was, it was kinda like, 'I don't know. I don't know how John is because John's not here anymore. It's somebody else,'" his brother, Mike Needham Jr., explained.
Growing up, Mike Needham Jr. often teased his younger brother, but when John came home from Iraq, Mike grew concerned. John was edgy, had mood swings and flashbacks -- symptoms of PTSD.
"I remember one time I woke him up, and I woke him up out of his sleep because he was crying in his sleep, and John had got up, and he went to the corner of the room and took off all his clothes and then got into like a fighting stance, like he was gonna fight me," he recalled. "And then I had to turn the lights. And I'm like [claps] - and I'm like John what are you doing? And then he snapped out of it."
To make matters worse, John Needham had severe back pain from combat injuries. He was prescribed a fistful of drugs and often downed them with alcohol.
"John was never a drinker, you know? Before he left, he -- he didn't drink alcohol," Mike Needham Jr. said. "But he came back and he would drink and drink and drink and he was...drinking, drinking the pain away."
The drinking escalated when Jacque Villagomez moved in with John Needham. John's father, Mike Needham Sr., lived upstairs.
"To me, it was throwing gasoline on the fire," he told Roberts. "I had talked to him and said...you know, it wasn't a good time to have a relationship and he needed to concentrate on his own rehabilitation."
But Villagomez stayed and their fragile relationship started to crumble. Three days before her death, she posted this angry message on John's Needham's MySpace page:
"I hope you...overdose on sadness ...regret will take over your life until you are in so much pain that you take your own life!"
Mike Needham Sr. put his foot down. On Sept. 1, 2008, he insisted it was time for Villagomez to go.
"I said, 'Jacque I'm going to give you some money, we are going to get you a hotel, motel and we are going to help you get on your feet,'" he said. "She wasn't happy about it at all. She was really, really kinda distraught, upset."
The couple wasn't ready to say goodbye. A store security camera captured an image of them holding hands and buying vodka for what would be their last alcohol-fueled night together.
"I think that for both of us, we were on a downward spiral and it got to a boiling point to where you know, something was gonna happen," John Needham explained. "What it was, whether it was me dying, her dying, someone was gonna die."
According to Homicide Det. Joe Gaul of the Orange County Sheriff's Department, "There was blood spatter on the doorjamb, the wall, the bathroom door -- what we call impact patterns, somebody being struck and the blood spraying off of being struck."
Det. Gaul learned the bloodshed was sparked by a jealous rage - Villagomez's. Earlier that evening, Jacque had finally agreed to move out. But just as she was leaving, an old girlfriend -- Renee Stoner -- showed up to visit John. Soon after, Jacque stormed back in.
"And Jacqwelyn was very upset that Renee was there at the house with John," Det. Gaul continued. "They got into a physical confrontation over that fact. John had separated both of them. And John was restraining Jacqwelyn while Renee escaped to the bathroom. Eventually John told her to get out of there."
Once outside, Stoner called 911, where she described Jacque Villagomez as the aggressor, not John Needham.
Renee Stoner: This girl just attacked me and ripped out half my f***** hair.
911 operator: And where is this girl at?
Renee Stoner: She's inside the house.
911 operator: Do you need the paramedics?
Renee Stoner: Um I don't know, she was hitting my head, but I feel fine. I'm just really shaken up.
"At that time [Stoner] didn't see any blood. She didn't witness any - beating or assault of any kind. She just left the scene," said Det. Gaul.
But something happened in the few minutes it took deputies to respond. When they found Jacque Villagomez, she was battered -- near death -- and would not survive. John Needham was naked, crying and smeared in blood. Deputies say Needham charged them and they had to use a Taser to subdue him.
"There was no evidence to indicate anything other than John's fists were used to beat Jacqwelyn," the detective said.
When Det. Gaul began his interview with John Needham, "he was still in a hospital gown. And his hands were wrapped in paper bags because we had already decided that we were going to try and extract some evidence from his hands down the road, we didn't want that to be contaminated."
Deputies on the scene say John told them Jacque had tried to break his nose. But when Det. Gaul and his partner questioned him ... John had few answers.
Investigator: What happened in that room? She had to do something to set you off, to pull the trigger, right?
John Needham: I don't know. (he cries)
Investigator: You do know John.
John Needham: I don't know! I don't know OK!? I'm a vet okay. I have issues, I get set off.
John never was able to provide a clear explanation for the killing. He says as he struggled to restrain Villagomez, something inside of him snapped.
"I see it as - just complete chaos," Needham explained. "Complete insanity. And--and I've--I see--myself being uncontrollable. I - I- turning into an animal. There's you know.... I never wanted this to happen."