Ali Kemp seemed to be leading a charmed life. The 19-year-old grew up in a loving home with her parents and two brothers in the idyllic setting of Leawood, Kan., a peaceful, tree-lined suburb just outside of Kansas City. By all accounts, she was a remarkable young woman, who dreamed of someday going to Russia to work with needy children. But she never got the chance.
On an overcast day in June 2002, Ali lost her life in a moment of terrible, senseless violence like nothing even veteran police officers in the community had ever seen before.
"I'd have to say that in my 35 years of experience it was probably the most horrific thing that could happen to a community like this," said Maj. Craig Hill of the Leaway Police Department.
Kemp had just finished her freshman year as an honor student at Kansas State University, and was working as an attendant at a neighborhood pool, just four blocks from her family's home.
"It was a wonderful job, a neighborhood pool. And you would think the safest place in the world," her father, Roger Kemp, told "20/20" correspondent Don Dahler.
But that June day, when overcast skies left few people at the pool, Ali was randomly confronted by a man in the pool's pump room. Moments later, he would brutally beat and strangle her.
At around 3 p.m. she called her friend Laurel Vine to come keep her company during her shift at the pool. She then called her boyfriend, Phil Howes, on his cell phone. But Howes missed her call. "I wish I could have answered that, because maybe she was in trouble then, and was trying to get hold of me."
Nothing seemed out of the ordinary when Vine pulled into the pool parking lot. "I saw a man walking out. I presumed he was a maintenance worker. And I just kind of looked around and saw Ali's stuff there. I just assumed that she had gone to do something really quickly. And then I left and went home," she said.
Found by Family
Two hours later, when Ali's brother, Tyler, showed up to relieve her of her pool duties, he noticed her purse and cell phone on a table but no sign of his sister. So he called his father, who came over to help find her.
"I looked around the pool, went into the poolhouse and I went in, I didn't see anything. And then I just took few more steps and then I found Ali. ... She'd been covered and her leg was sticking out. ... I threw back the cover and there she was," her father recalled tearfully.
Det. Joe Langer got the call, and arrived at the crime scene to find evidence of a violent struggle and a girl who'd been brutally beaten.
"She was fighting for her life and unfortunately lost that fight," Langer said.
When Vine heard the terrible news, she immediately thought about the man she saw earlier. "I thought, 'Oh, my God, I just saw her killer and I didn't know it,'" she said.
With a killer on the loose, the community was terrified. Forty detectives from the Kansas City area fanned out looking for leads.
The police asked Vine to sit down with a forensic artist and describe the man she saw.
Leawood's tiny police department was stretched to the limit. "They never left one stone unturned. They wanted to find this individual," Hill said.
But eight months passed and Ali's killer was still at large. Everyone was becoming increasingly discouraged.
Innovative Idea Pays Off
But Kemp would not rest until his daughter's killer was caught. He decided he had to do something to help catch the murderer. His idea was something that had been literally staring him in the face everyday on his way to work: billboards.
"I was going down the highway and I looked at them and I thought, why not? Why not give them a call and see what a billboard costs, and that's what I did," he said.
Bob Fessler of Lamar Advertising, which owned the area billboards, was surprised by Kemp's unusual request, but he wanted to help.
"I never thought we'd be involved in solving crimes," he said. "He was fully prepared, I believe, to come in and buy one or two billboards and put them up to help generate leads -- to catch the guy that killed his daughter," Fessler said of Kemp.
But Lamar Advertising wouldn't let Kemp buy a billboard. Instead, they donated one.
Billboards had been used to find missing persons, but never before to solve a murder.
Maj. Hill was impressed by the idea. "When Roger came to me and said what do you think? I thought that's perfect. It'll be awesome, because a newspaper, you read it, it's tossed in the trash. Television, it's aired, it's gone. Billboard, it sits there 24 hours, seven days a week," he said.
And the billboard donated to help Kemp sat where 50,000 pairs of eyes saw it every day. There was an immediate response. "The first week, we were probably pulling 100, 150 tips off the first billboard. They just came rolling in," he said.
Two people recognized the man on the billboard and called in. Finally, more than 2 years after Ali's murder, those tips led authorities to a house in Bantam, Conn., 1,300 miles away. Police moved in and arrested 30-year-old Benjamin Appleby in November 2004.
Roger Kemp's billboard idea was the key to catching the man suspected of killing his daughter. But his pain wasn't over: he had listen to the description of Ali's last moments from Benjamin Appleby's chilling confession tape that was played in court.
Appleby describes seeing Ali in the pool's pump room. He said he found her attractive and approached her with the intention of "hitting on her." In a taped confession, Appleby told officers she rejected his advances and pushed him when he reached out to touch her. "I touched her not hard nothing either on the shoulder or the hip or something and she pushed me back and she punched me. I f--in' lost it. I hit her back. I know I f---ing killed her and I don't know why I did," he said in his taped statement to the officers.
Despite the confession, Appleby has pleaded not guilty, and the trial continues.
Father Still Fighting Crime
Helping capture his daughter's alleged killer wasn't enough for Kemp. He launched a campaign to use billboards as modern day "wanted" posters to catch other killers. In the past three years, the arrests of suspected murderers Cornelius May, Phillip Hughes, and five other fugitives in the Kansas City area alone can be directly attributed to those billboards. And the program has caught on in other states as well, including Michigan, New Jersey, and Louisiana. Even America's Most Wanted is now using billboards as crime-fighting tools.
"I don't know why people haven't done it before. In looking at the billboards, I thought it might be a good avenue and it's worked out to be a great avenue," Kemp said.
As relentless as he was in pursuing his daughter's killer, Kemp is equally devoted to helping families avoid the pain his family lives with. Because he knows his daughter fought hard for her life, but lost that fight, Kemp started a self-defense class. So far, some 2,000 people have attended.
"We don't want it to happen to another little girl. We don't want it to happen to their family," he said.