The family of Tiger King star Carole Baskin's former husband, who disappeared in 1997, are offering a $100,000 (£76,000) reward for information to help find out what happened to him.
Don Lewis vanished after leaving his home in Tampa, Florida, a day before a scheduled trip to Costa Rica and was never found. He was declared legally dead in 2002.
His relatives' lawyer John Phillips said an independent investigation will take place, and on behalf of the family he has filed a lawsuit against Lewis' second wife, Baskin, in an attempt to depose her and get her to speak on the record.
Mr Lewis and Baskin started an animal sanctuary, which later became Big Cat Rescue Corporation in Tampa, and his disappearance as well as the facility featured in the hit Netflix show Tiger King: Murder, Mayhem and Madness.
Image: Joe Exotic is now serving 22 years in prison for his role in a murder-for-hire plot against Baskin. Pic: Netflix
The documentary series centred on Joseph Maldonado-Passage, also known as Joe Exotic, an eccentric former Oklahoma zookeeper who loves big cats.
Earlier this year, Maldonado-Passage was sentenced to 22 years in prison for his role in a murder-for-hire plot. He is currently in jail.
He was convicted of trying to hire someone to kill Baskin, who had tried to shut him down, accusing the Oklahoma zoo of abusing animals and selling big cat cubs.
In retaliation, Maldonado-Passage raised questions about Baskin's former husband, Jack "Don" Lewis.
The documentary extensively covered Maldonado-Passage's repeated accusations that Baskin killed her husband and possibly fed him to her tigers.
Baskin has not been charged with any crime and has repeatedly released statements refuting the accusations made in the series.
Image: Baskin's Big Cat Rescue was granted control of Exotic's zoo in June. Pic: Netflix
Three of Lewis' daughters were at a news conference where the $100,000 reward was announced.
The family and the lawyer have paid for Tampa-area billboards asking for information.
Lewis' youngest daughter, Gale Rathbone, expressed gratitude for those interested in the case.
Ms Rathbone said: "Amazingly, our little family tragedy has become your tragedy. Our search for closure and truth has become your mission also.
"We all know by now that (Lewis) was not a perfect man. But do only the perfect among us deserve justice?"
In an email to the Associated Press, Baskin said she wouldn't comment.
Baskin wrote: "It's been my policy not to discuss pending litigation until it's been resolved.
"I had told some news outlets that I thought the press conference on 10 August was just a publicity stunt, but at that time was not aware there would be pending litigation."
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Baskin is still the owner of Big Cat Rescue, and lobbies for abolishing private wildlife ownership.
She previously sued Maldonado-Passage for trademark and copyright infringements and won a $1m civil judgment against him.
The judge found that ownership of the Oklahoma zoo that was previously run by Maldonado-Passage had been fraudulently transferred to his mother in an attempt to avoid paying the judgment.
Baskin's Big Cat Rescue Corporation was granted control of the zoo by a federal judge in June.
In March, the Hillsborough County sheriff asked for tips in the case of Lewis and announced a reopening of Lewis' case.