Produced by Patti Aronofsky and Gayane Keshishyan
[This story previously aired on May 29, 2012. It was updated on March 23, 2013.]
(CBS) ORANGE COUNTY, Calif. -- The murder of Bill McLaughlin rattled the quiet gated community of Balboa Coves and devastated Bill's daughters, Jenny and Kim.
"My mom called and told me. It's too terrible to hear. Somebody had come into our house and shot him in the chest," Kim McLaughlin told "48 Hours" correspondent Troy Roberts.
On Dec. 15, 1994, Newport Beach detectives struggled to piece together the puzzle.
"To have a murder occur here was very uncommon," said Tom Voth, who was the lead detective on the case. "There were no fingerprints. DNA was very early in its stages... There were no weapons found."
"So there wasn't much to go on?" Roberts asked.
"No, no sir," said Voth.
But the night before his murder, Bill McLaughlin had called his brother, Patrick.
"I could tell right away something was wrong...he was in Las Vegas calling me," Patrick McLaughlin told Roberts. "...he was feeling as though his life was threatened. Just the way he talked to me. It was like people were out to get him."
"And we were very worried for our own safety," Kim explained. "Who has done this? Are they after the family?"
Detectives began pouring over every personal detail of Bill McLaughlin's life. His world of privilege in Newport Beach, Calif., was a far cry from his humble beginnings on the south side of Chicago.
"He was always the self-made guy, really," said Patrick.
He was first in his family to go to college.
"He wanted to be the kind of guy that would make a difference," Patrick continued.
And he did. Bill McLaughlin was the entrepreneur behind the development of a groundbreaking device that separated plasma from blood. It was a huge advance in the healthcare field and it made him a fortune.
Bill's best friend, Don Kalal, says McLaughlin was "probably [in] his early 30s" when he made his first million. But Kalal says that was just the beginning. By the time of his death, McLaughlin was worth an estimated $55 million.
"You don't amass that kind of fortune without stepping on some toes," Roberts noted.
"There was nobody that I knew that had a vendetta against him," said Kalal.
But in the months before his murder, Bill had been embroiled in a bitter lawsuit with Hal Fischel - a former business partner who had invented the plasma device.
"This had been a long difficult lawsuit," Jenny McLaughlin explained. "Hal Fischel was the adversary in the lawsuit."
Fischel lost the suit and had to forfeit $9 million to McLaughlin. That sounded like a motive.
Voth said he considered Fischel a suspect in the case. But Fischel had an alibi - a good one. Eyewitnesses say he was in Santa Barbara, nearly a 150 miles north of Newport Beach, at the time of the murder.
Voth said Fischel was eliminated as a suspect "fairly quickly."
Besides, investigators were becoming more convinced the killer was part of Bill McLaughlin's inner circle. The clues kept leading them closer to home; in fact, directly to his front doorstep.
"When we arrived at the homicide scene in 1994, there were two keys located - we found the key in this door," Voth showed Roberts at the crime scene. "In addition, they also found a key laying on the ground here. And the key that fits this lock right here, at the time also fit the front door of the residence."
"What does that say?" Roberts asked.
"In all of our minds, that narrows the field of suspects down to those who have access to keys," Voth replied.
Police took a closer look at McLaughlin's family, beginning with his son, who was upstairs in the house when he says he heard the shots that killed his father.
"They put paper bags over Kevin's hands and they did a forensic analysis of his hands, showing that Kevin did not fire a firearm that night," said Orange County Deputy District Attorney Matt Murphy.
That left McLaughlin's two daughters and his ex-wife, all who had airtight alibis and no motive.
And then there was Nanette Johnston -- Bill McLaughlin's much-younger fiancee, who he met through a magazine ad she placed looking for a wealthy, older man.
"'I know how to take care of a man. If he can take care of me.' That's what she said," Patrick said of the ad.
"He was at a vulnerable time," Kim said. "And so here she comes along and, you know, made everything a little better."
In return, Bill McLaughlin provided Nanette with a generous allowance and a lavish lifestyle.
"She immediately stepped into a lifestyle that most people would only dream of," Murphy explained. "She lived in a beautiful home. They went to Europe, they went on cruises, they went on exotic ski vacations. She had...jewelry, everything."
Within months, Nanette brought her two young children to live with Bill. His daughters, Kim and Jenny, became increasingly worried
"I said, 'Dad, I don't really like her. I think she's with you for your money," said Kim.
"She knew how much he was worth," noted Roberts.
"Yes, definitely," she replied.
In spite of the warnings, McLaughlin proposed after about a year of dating.
"And she told everyone she was his fiancee," said Jenny.
"She had a whopper of a ring," added Kim.
McLaughlin even wrote Nanette into his will.
"He wanted to make sure that if anything happened...her and her kids would be taken care of," Murphy explained. "...he had a million dollar life insurance policy with her as the beneficiary."
On Dec. 15, 1994, Bill McLaughlin came home and found a note from Nanette. She had gone to her son's soccer game and would be home late. When she pulled up to the house around 10 p.m., her fiance was dead.
"What was Nanette's alibi?" Roberts asked Voth.
"That she was at the soccer game. And directly after that she went shopping. She couldn't have possibly been involved in the murder because she had these receipts," he replied.
"Did her alibi check out?"
"No. Not completely."
Nanette had been at the soccer game, but with another man -- someone McLaughlin's family knew nothing about.
According to Jenny McLaughlin, "They said, 'Do you know who Eric Naposki is?' And we said, 'Absolutely not, who's that?' They said, 'This is Nanette's boyfriend. And we were like, 'Really? We thought our Dad was Nanette's boyfriend."