Emergency room physician John Forsyth sent a text to his fiancée in the early morning hours of May 21. He'd just finished his overnight shift at the hospital, he told her, and would see her in a little bit.

Then he abruptly stopped responding to messages, said his brother, Richard Forsyth. And that's the last time his loved ones heard from him.

Surveillance footage from that day showed the doctor walking toward his RV outside the hospital in Cassville, Missouri, his brother said. Investigators told the family they found his Infiniti sedan unlocked at a nearby park. Inside the car were his two cell phones, wallet, passport, driver's license, his work briefcase and the keys to his car and RV, Richard Forsyth said.

To the family, this was a sign that something was terribly wrong. Forsyth never went anywhere without his phones in case he got calls about his patients, his brother said.

The family spent frantic days searching and posting missing-person notices on social media before a kayaker discovered Forsyth's body Tuesday afternoon in northwest Arkansas' Beaver Lake, the Benton County Sheriff's Office said in a statement.

The body was found near the shore, about 20 miles south of Cassville, and had an apparent gunshot wound.

It's a tragic end for someone who appeared to be starting a promising new life chapter. John Forsyth had proposed to his girlfriend three days before he disappeared and was looking forward to the future after his divorce was recently finalized, his brother said.

"The last few days have been hell. We are devastated," Richard Forsyth told CNN. "We were all gathered at dinner with family, extended family, and John's fiancée when the state police came to report that his body was found. We've been reeling since the news. The revelation about him being shot has sent new ripples of anguish."

Surveillance footage showed his car at a local park

The discovery of Forsyth's remains has stunned the community of Cassville, a city of about 3,000 people in the Ozarks of southwestern Missouri, not far from the Arkansas line. Forsyth was a doctor at the town's Mercy Hospital, where his family says he'd worked for two decades.

Forsyth, 49, was last seen about 7 a.m. local time on May 21, the Cassville Police Department said in a statement. He was reported missing the next morning after he didn't show up for his shift without notifying anyone.

Forsyth was so passionate about his job that he slept in his RV in the hospital parking lot when he had back-to-back shifts -- so his missing work raised a red flag, his brother said.

Family members had organized search parties and launched a Facebook page to help find answers. John Forsyth's patients shared messages on the page about their positive experiences with him. Amateur sleuths pored over scraps of information and posted theories.

With every new detail, more questions emerged.

Richard Forsyth, 47, said police told the family that surveillance cameras showed the doctor walking toward his RV near the hospital on the morning of May 21. Surveillance footage also captured his car arriving at a Cassville aquatic park shortly afterward and a white SUV pulling up near him. The doctor then got out of the car and walked away, but it's unclear where he went, Richard Forsyth said.

Finding personal items such as Forsyth's phones in his car was another red flag, his brother said.

"He was never without these essentials," Richard Forsyth said. "It said something was terribly wrong."

Forsyth had plans to visit his children out of state the next day

Dana Kammerlohr, Cassville's police chief, confirmed that Forsyth's body was found in Benton County, Arkansas, but declined to provide more information, citing an ongoing investigation.

The Benton County Sheriff's Office said their investigation is ongoing and they cannot release any details.

Meanwhile, Richard Forsyth said his brother's death has left the family stunned.

The father of eight was not only recently engaged, he had plane tickets to leave the next day for Idaho and Utah to visit some of his children, his brother said.

John Forsyth had recently finalized his divorce and was ordered to pay thousands of dollars a month in alimony and child support, Richard Forsyth said.

"John Forsyth is a beloved son, brother, father, and member of the community. He has served others as a physician for over twenty years. Nothing in life can prepare a family for the worry and heartbreak that comes with a nightmarish situation like this," the family posted on social media.

His sister, Tiffany Forsyth, implored investigators to help the family find answers.

"I've often felt like Johnny and I are two sides of the same coin. Our lives have led us in very different directions, but in the last couple of years we've been bonding over our intense desire to understand the mysteries of the universe, and I've treasured those conversations like precious jewels," she posted on Facebook after her brother went missing but before his body was found.

"I rarely meet anyone I can toss around ideas with like he can ..." she added. "We have so much more to talk about."

Richard Forsyth: 'He was the happiest I'd ever seen him'

Days earlier, on May 17, the two brothers met for dinner at a local restaurant, Richard Forsyth said. The two brothers dabbled in cryptocurrency and talked about their business ideas.

"We talked about a lot of things ... how happy he was. We talked about our cryptocurrency project ... we talked about life. Our plans to renovate a building," Richard Forsyth said.

His brother did not mention any fears or concerns over the dinner, Richard Forsyth said. In the past, however, John had made comments that sound worrisome in the context of his disappearance, he said.

"On several occasions, he's talked about scenarios ... (in case) he wasn't around anymore," Richard Forsyth said. "Continuity plans."

Investigators told the family they are working on retrieving information from John Forsyth's phones.

Meanwhile, Richard Forsyth maintains he has no reason to believe his brother died by suicide.

"I can give a TED Talk on why my brother did not kill himself," he said. Richard Forsyth added that as far as he knows, his brother didn't own a gun.

"This is a man who just got recently engaged, he was involved in philanthropic work and other projects he was passionate about, he was making plans for the future. He loved his kids and was so proud of them. He was devoted to them and had plane tickets to go see them. He described his fiancée as the love of his life," Richard Forsyth added.

"He was the happiest I'd ever seen him in his life. He'd even started a garden. This is not a profile of someone who killed himself."