Draper • A Utah man serving a life prison sentence for a 1984 double murder he believes was directed by God says his ideas likely influenced a couple's decision to fatally overdose along with their children.

Dan Lafferty sees himself as a prophet who will prepare the world for the Second Coming. He has little following, but 10 years ago he started a relationship with a young woman named Kristi Strack, who was drawn to him after reading a book chronicling the slayings that put him in prison.

In September, Kristi Strack and her husband, Benjamin, and three children overdosed on a combination of methadone and cold medicine, a deed that Lafferty says was influenced by his ideas and philosophy.

They hadn't been in touch for at least a year before the deaths, but police said the family talked often about their fear of an impending apocalypse. In a Thursday interview with The Associated Press conducted behind a Plexiglas panel at the Utah State Prison, Lafferty said he sees himself as the prophet Elijah and the world as hell, controlled by the devil, a philosophy that he said likely influenced the Strack family's suicides.

The 66-year-old Lafferty says he first became close to the couple after Kristi Strack had a dream about him while she was reading the 2003 Jon Krakauer book "Under the Banner of Heaven," which chronicled Lafferty's slayings of his sister-in-law Brenda Lafferty and her 15-month-old daughter.

She reached out to him, and eventually Kristi and Benjamin Strack became almost weekly visitors to the Utah State Prison.

Lafferty said he and Kristi Strack fell in love, something her husband was aware of and didn't mind. At one point, Lafferty cut off his waist-length hair and beard at her request and sent them to the family.

Lafferty said that he would often spend hours a day talking on the phone with the Stracks, racking up phone bills in the thousands of dollars. Some of those conversations were sexual, and Kristi once shared a photo of herself in her pajamas, he said.

During their conversations, they discovered that Lafferty had connections to both Stracks when they were children and he was living not far away in Utah County. As the friendship developed, they talked about his philosophy and Kristi Strack shared dreams she had about it. He believes the apocalypse is coming soon, though he said Thursday that he's thought the apocalypse was coming since he entered prison 30 years ago.

Rick Ross, executive director of The Cult Education Institute, said Lafferty is a cult leader with a small following who can nevertheless wield a deep influence.

"With Lafferty and those that pose as prophets, they all created a kind of doomsday, crisis mentality where people felt there was nothing in the world left to live for," said Ross, who authored a book on why people join cults and how to get them out. "When they killed themselves, they felt like they were doing something that was good."

Even from behind prison walls charismatic leaders can have an influence, Ross said.

Lafferty killed his sister-in-law and her daughter after she resisted her husband's entry into a radical group that espoused polygamy and other early Mormon ideas. His brother, Ron Lafferty, is on death row after his conviction in the slayings.

The relationship between Lafferty and the Stracks tapered off after the couple pleaded guilty to criminal charges including forgery and drug possession in 2008, which ended their prison visiting privileges.

They exchanged letters afterward, but Lafferty said Kristi Strack didn't believe he was Elijah, and when he persisted she quit answering his letters.

Lafferty says he hadn't talked to the couple for years and didn't know of their plans or mindset.

"I'll miss them, but I'm happy for them," he said. "I believe they're in paradise now."

Lafferty is polite and friendly in conversation. He has a slight build and wears tortoise shell glasses, his hair neatly combed with a small beard. He eyes got red and his voice caught with emotion when he talked about his brief brushes with the Stracks as children.

He spends his days doing yoga, reading novels and taking naps, and says he hasn't gotten many people interested in his case like the Stracks. He refers to his philosophy as his insanity; though he says he's not crazy.

"My 'insanity' messes with people's lives," he said. "It's just the way it is."

Police wrapped up their investigation into the deaths of the Strack family this week, saying they purposely overdosed after talking for years about growing evil in the world and wanted to escape from "impending doom."

They didn't leave any suicide notes or recent writings to explain their mindset, and Springville police Cpl. Greg Turnbow has said there was no apparent event that trigged the suicide.

Lt. David Caron said Thursday that Lafferty initially denied influencing the Stracks, and said the relationship was more fatherly. Police interviewed Lafferty during their investigation, and found that he'd had no recent contact with the couple and was unaware of any suicide plans.

FILE - In this June 30, 2003, file photo, Dan Lafferty poses for a photograph, at Utah State Prison in Draper, Utah. A Utah couple who overdosed on drugs along with their three children was obsessed with Lafferty, a murderer who sees himself as a prophet. Kristi and Benjamin Strack visited Lafferty for years before their visiting privileges were cut off, developing a close friendship as part of an increasingly bizarre mindset that culminated with a belief that the apocalypse was near. (AP Photo/Douglas C. Pizac, File)
Chief Scott Finlayson speaks during a news conference about the Strack family on Tuesday, Jan. 27, 2015, at Springville, Utah. Police said they will release the conclusion of their investigation into the deaths of five members of the Utah family found in a single bedroom last fall. (AP Photo/The Daily Herald, Sammy Jo Hester)
FILE - In this Oct. 2, 2014 file photo, flowers and photos are on display during a vigil for the Strack family at Pioneer Park in Provo, Utah. Police say five members of the Utah family found dead last fall died from methadone and other drugs, and interviews with people who knew them revealed the parents worried about a "pending apocalypse." Springville Police Chief J. Scott Finlayson said Tuesday, Jan. 27, 2015, authorities have concluded their investigation into the September deaths of Benjamin and Kristi Strack and three of their children, ages 11, 12 and 14. (AP Photo/The Daily Herald, Grant Hindsley, File) MANDATORY CREDIT
Lt. Dave Caron speaks during a news conference about the Strack family on Tuesday, Jan. 27, 2015, at Springville, Utah. Police said they will release the conclusion of their investigation into the deaths of five members of the Utah family found in a single bedroom last fall. (AP Photo/The Daily Herald, Sammy Jo Hester)
FILE - This Sept. 28, 2014, file photo, shows the home where five Utah family members were found dead in their home, in Springville, Utah. Police say five members of the Utah family found dead last fall died from methadone and other drugs, and interviews with people who knew them revealed the parents worried about a "pending apocalypse." Springville Police Chief J. Scott Finlayson said Tuesday, Jan. 27, 2015, authorities have concluded their investigation into the September deaths of Benjamin and Kristi Strack and three of their children, ages 11, 12 and 14. (AP Photo/Rick Bowmer, File)
Chief Scott Finlayson speaks during a news conference about the Strack family on Tuesday, Jan. 27, 2015, at Springville, Utah. Police said they will release the conclusion of their investigation into the deaths of five members of the Utah family found in a single bedroom last fall. (AP Photo/The Daily Herald, Sammy Jo Hester)
Chief Scott Finlayson speaks during a news conference about the Strack family on Tuesday, Jan. 27, 2015, at Springville, Utah. Police said they will release the conclusion of their investigation into the deaths of five members of the Utah family found in a single bedroom last fall. (AP Photo/The Daily Herald, Sammy Jo Hester)