Lesa Buchanan died on the Fourth of July weekend in 2005, after spending a good portion of time with her boyfriend, Dr. Christ Koulis, having sex. Koulis, a plastic surgeon, called 911 when she stopped breathing, and says he performed CPR but that there was no pulse.
Investigators quickly focused on drugs. Prosecutors allege Dr. Koulis had injected Lesa with a powerful painkiller during the course of the weekend, which eventually led to her death.
But Koulis claims Lesa injected herself, and that she had a drug problem - a claim her family and investigators have disputed.
As correspondent Troy Roberts reports, the case ended up in the hands of a jury, who had to decide if the doctor was responsible for his girlfriend's death.
When police were called to Lesa Buchanan's apartment in Franklin, Tenn., they were surprised by what they found in her home: a cache of prescription drugs and sex toys.
Detectives videotaped the scene, where lead investigator Eric Anderson says they found "a lot" of syringes.
Lesa and Koulis had spent most of that final Fourth of July weekend in her bedroom. "They stayed in that apartment that weekend engaged in this marathon sex session," Anderson says.
The detective says collecting all the evidence was a massive undertaking.
Most crucial, say detectives, was the discovery of used syringes, with traces of oxycodone. Oxycodone is a powerful narcotic used to kill pain; it can be a very addictive and dangerous drug. Abusers like the calming euphoria it creates, the high is immediate and potent.
"It's a controlled substance. It's something you can only get from a prescribing physician, you can't just buy it," Anderson says.
But when Lesa was rushed to the emergency room, the doctors trying to save her life say Dr. Koulis told them nothing about the drugs she had been using. In fact, paramedics say Koulis claimed Lesa collapsed after a trip to the swimming pool.
"Christ was deceptive. He totally misled them," Anderson says. "Christ stood there in that E.R. room and didn't tell them about the illegal drugs, didn't tell the E.R. staff what could have been crucial in saving her life."
Tara Bentley believed her younger sister Lesa did not see Koulis as she did. "I think that the rest of us just felt that any day now she would realize who he was," she says.
On paper, Koulis looked pretty good. He was a young, handsome, plastic surgeon. A graduate of Vanderbilt University, he had a thriving practice by the time he was 30. Koulis had served his internship at a Chicago hospital and loved working in the emergency room.
It was in Nashville in 2000, that Koulis had a chance meeting with Lesa. He became her boyfriend and her doctor.
Koulis says he performed numerous procedures on Lesa for free. Asked how many, he says, "A re-do breast augmentation, her eyelids, forehead, lip augmentation, liposuction. Full face laser, Botox, collagen, the list goes on."
Lesa was a struggling to make it as an actress and model. Even at a young age, she had big dreams for herself. She auditioned for soaps, and tried out for TV shows. Her most recent pursuit was to develop a children's puppet show.
But things just never clicked for Lesa, professionally or personally.
Before Koulis, Lesa has a string of failed relationships. She married young and divorced. But from that broken marriage came one of the best things in her life: her daughter Jesse.
Jessie was happy at first when her mother met Koulis. "We just moved into this big house, and that was so cool. I got a huge room and my girlfriends came over and we had a huge, big screen TV on the wall and I thought it was cool," she remembers.
But it wasn't long, says Jesse, before she noticed how controlling the doctor was. "Once I got to know him I really didn't like him. He would always call her every ten minutes wanting to know where she was. It was stalkerish. He was just so protective in a creepy kind of way," she says.
Lesa and Koulis were on again, off again for five and a half years, and according to her sister Tara, Lesa was just about to break things off again that final weekend.
Tara had wondered if Lesa could ever break away. Lesa appeared locked in Koulis' grip even though the couple spent much of the relationship apart. He lived and practiced in other cities, and frequently called Lesa, accusing her of seeing other men.
And there was something else that concerned Lesa's family: her mother Peggy says Lesa was becoming ill more frequently. In fact, her family believes that Koulis would convince Lesa she was sick, and that he alone could fix her.
Asked if she ever saw Koulis give her mother drugs, Jesse says, "Yes."
She says she has a vivid childhood memory of seeing Koulis inject her mother with an unknown drug. "She fainted and I started screaming 'Mommy' and he shut the door, the bathroom door. I started banging on the door and he wouldn't let me see her," Jesse says.