"When I look back, I wish that maybe I'd listened a little more or been there a little more because she was always there for me," Mischelle's best friend, Melissa Gaines, told "48 Hours Mystery" correspondent Erin Moriarty.
It's still not easy for Gaines to read the cheery diary that Mischelle kept the last year of her life:
"January 1st. Slept real late. Family went to Mingo and I went to Leon's. We loved and ate and talked and rented movies. Made me feel loved today and I am really happy. Love him. Great first day of 1992!"
Gaines met Mischelle when they were high school freshmen in Benton, Mo.
"I had just moved to Kelly High School, didn't know anybody," she said. "Her little bubbly self came bouncing up and introduced herself and it was all over. She was part of my life from that moment on."
While Mischelle stood barely five feet tall, she was no lightweight. She was a green belt in karate - halfway to earning a black belt.
"I can't even remember anything she was ever scared of," Gaines recalled. "She was fearless."
"Would it ever occur to you that Mischelle might be in danger?" Moriarty asked.
"No. I mean, that never was a thought to me. Never."
Which is why what happened in the early morning hours of Nov. 8, 1992, was so unexpected and so shocking.
Rick Walter was a 32-year-old part-time deputy sheriff when he discovered the body of Mischelle Lawless.
"This is small town USA. A lot of stuff like this just doesn't happen," Walter said of the brutal murder.
Police documented the grisly scene using blood evidence to reconstruct Mischelle's final, terrifying moments.
"I believe she got out of the vehicle, and I think there was an argument," Walter explained. "She ended up over the guardrail and down the bottom of the slope. A very violent altercation took place. I believe she was beat at the bottom and knocked unconscious. There was a lot of blood…"
There was also blood under Mischelle's fingernails and marks on her right hand and wrist suggesting she had fought her assailants.
"I think that she was fighting for her life. I think she was fighting more than one person," Walter said. "There was a blood trail going back up the hill. They carry her across the guardrail. They put her back in the car."
It wasn't until investigators searched her car and found three spent shell casings from a .380 caliber handgun that they realized Mischelle had been shot, too.
"I think after she got back in the car, I think that's when she regained conscious and somebody reached through the window…shot her point blank in the face; shot her in the back of the head. And then one more time in the back," Walter said, pausing. "I can't imagine what she went through that night."
Investigators canvass the crime scene
At the same time the deputy sheriff was working the crime scene, a 23-year-old local man walked into the sheriff's office with a surprising story.
Mark Abbott reported that he had also seen the woman in the car.
"Scared me. I never really saw anything like that… All I remember is her face was just matted and covered with hair and blood," he told Moriarty. He said he didn't know who the woman was.
Abbott told the dispatcher he thought the woman had been shot and that he had tried to call 911, but a nearby pay phone was out of order.
"I pulled outta there as fast as I could and went straight to the county sheriff's department trying to get an ambulance," he said.
As he was leaving, Abbott saw - as he described to investigators - a white car with several dark skinned Hispanic men driving away from the crime scene.
"Well, a man for sure, and two or three other people," Abbott said.
Mischelle's family got the news when authorities came to their door.
"I answered the door. It was about 3 a.m. I guess," said Jason Lawless, who was 15 when his older sister was killed.
"I don't do this well," he told Moriarty, overcome with emotion. When asked how Mischelle's death affected his family, he said, "Whoever shot my sister, killed my family - every ounce of it, every fiber that held it together."
The first suspect was the last person to admit seeing Mischelle alive: Leon Lamb, the boyfriend she stopped to see.
"She was only there about an hour or so, so it coulda been 11:30 or 12:00 at night," Lamb said of Mischelle's arrival. He said she left "just right at 1:00 a.m."
"January 6th: Called Leon and told him I love him so much..."
Lamb said Mischelle was his first love. From the entries in her diary, Mischelle clearly loved Lamb; but they also argued frequently. Mischelle was hurt that he was seeing other girls.
"No matter how mean he is to me, I still love him..."
Lamb said things were fine that night, although he remembered Mischelle was reluctant to leave his house.
"Now that I look back, it seemed like that she knew something was wrong, maybe something was gonna happen," he said.
Investigators looked closely at Leon Lamb, but they could find nothing to tie him to the scene and he passed a polygraph.
"Did you think it could be Leon?" Moriarty asked Gaines.
"He never crossed my mind, no. I just could never imagine him wanting to harm her like that, ever."
Weeks went by with few other leads and no arrests. Finally, four months after Mischelle's murder came a big break.
Several inmates at the county jail reported that a 17-year-old Illinois boy who had been held there briefly on an assault charge had confessed to killing Mischelle Lawless. His name was Joshua Kezer. When Mark Abbott was shown a photo lineup, he picked out Kezer as the driver he saw near the crime scene.
"Did you say 'Yeah, this is the guy I saw; I know it.'" Moriarty asked Abbott.
"No, no…" he replied. "I said, 'It looks like him and that looks like the car.'"
That's all investigators needed. Joshua Kezer was charged with the first-degree murder of Mischelle Lawless.
"I sat there stunned, I immediately started to just be shaking and confused and I didn't know what was happening," Kezer said. "I just knew that something very real was happening."
Mischelle's family and friends were just as stunned. Neither Jason Lawless nor Melissa Gaines had ever heard Kezer's name mentioned.
"There was no truth to what they were presenting," Kezer said. "Everything was a lie."