What happened to John Forsyth, the Missouri doctor found dead in a lake? What we know.

Police were investigating Thursday to find out what happened to a Missouri emergency room doctor who went missing only to turn up dead with an apparent gunshot wound in an Arkansas lake more than a week later.

Dr. John Forsyth, 49, was last seen on May 21 and didn't show up for his shift in the Cassville, Missouri hospital where he worked. His body was discovered by a kayaker on Tuesday in Arkansas, authorities said. What happened to him in between is still largely a mystery.

His family members said in interviews and on social media that Forsyth was dedicated to his job and never would have missed a shift. His brother, Richard Forsyth, told news outlets that the doctor even sometimes slept in an RV parked near the hospital so he wouldn't miss a call about one of his patients.

Here's what we do and don't know about Forsyth's disappearance and death:

Where and when did he go missing?

Forsyth showed up to the hospital in Cassville, a small town of about 3,100 residents in the Missouri Ozarks, the morning of May 21. He texted his fiancée that morning at about 7 a.m., and said he would see her later, his brother Richard Forsyth told CNN. He stopped replying to messages after that.

He didn't show up for his afternoon shift, his brother told The Daily Beast.

“He wouldn’t miss a shift even if his eyeballs were hanging out of their sockets," Richard Forsyth told The Daily Beast last week. “It was an immediate red flag.”

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Forsyth's vehicle, a black Infiniti, was later found at an aquatic park in Cassville. It was unlocked with items including his wallet, two phones, and a laptop inside.

“It doesn’t seem like a person who left with a plan,” Richard Forsyth told the Associated Press.

Where was he found?

Law enforcement agencies, including the Missouri State Highway Patrol, used dogs and drones to search a nearly 9-mile radius around the aquatic park where the car was found.

It wasn't until earlier this week that a kayaker in Arkansas found his body in Beaver Lake, a large reservoir in northwestern Arkansas, about 20 miles away from the car.

How did he get there?

Authorities have said they're still investigating what happened to Forsyth after he was last seen.

Cameras spotted Forsyth's car arriving at a parking lot at the aquatic park, according to Richard Forsyth. A few minutes later on the footage, a white SUV was seen parking near it. Richard Forsyth said the cameras caught Forsyth walking away, but it wasn't clear where he went.

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The reservoir where Forsyth's body was found by the kayaker is about 26 miles away from the hospital where he worked and where people last saw him alive, according to his brother.

Richard Forsyth told AP on Wednesday evening that authorities hadn't given the family any new information, but were investigating the death and how he went missing.

How did Forsyth die?

Forsyth had what appeared to be a gunshot wound when he was found, the Benton County Sheriff’s Office said in a statement. Authorities didn't say what part of his body was shot or whether they believe Forsyth was shot by someone else or if the gunshot wound appeared to be self-inflicted.

Forsyth's family members rejected the idea that he could have killed himself.

"John would never do that. I won’t accept that possibility," Richard Forsyth, his brother, told AP.

Richard Forsyth told CNN his brother didn't exhibit any signs that would indicate he was suicidal. He said Forsyth had recently purchased plane tickets to visit some of his eight children in another state, and had just recently gotten engaged to "the love of his life."

He'd also recently finalized a divorce and been ordered to pay thousands of dollars every month in alimony and child support, Richard Forsyth told CNN. Finalizing the divorce May 11 "gave him energy for the future," he told AP.

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Richard Forsyth told the outlet that his brother had made statements in the past that in hindsight could be considered concerning.

"On several occasions, he’s talked about scenarios … (in case) he wasn’t around anymore,” Richard Forsyth told CNN. "Continuity plans."

But Richard Forsyth said he met for dinner with John Forsyth days before his disappearance and he was the happiest he had ever been in his life.

Contributing: N'dea Yancey-Bragg, USA TODAY; The Associated Press