(CNN) — There were no signs of foul play in the death of a US Centers for Disease Control and Prevention epidemiologist, said Fulton County Chief Medical Examiner Dr. Jan Gorniak.
The preliminary cause of death is drowning, Gorniak told reporters at a Thursday press conference, but the manner of death has not been determined. The investigation is ongoing.
A body recovered this week from a river in Atlanta has been identified as the US Centers for Disease Control and Prevention epidemiologist who vanished in February, Atlanta Police Department spokesman Carlos Campos said Thursday.
The remains of Timothy Cunningham, 35, were found Tuesday in the Chattahoochee River in northwest Atlanta, Campos said.
A news conference is set for 2 p.m. ET Thursday. The Atlanta Police Department, the Fulton County Medical Examiner's Office and the Atlanta Fire Rescue Department will participate.
Cunningham, of Atlanta, was last seen February 12, shortly after a CDC supervisor told him why he was being passed over for a promotion, police have said.
The disappearance prompted a high-profile police search and a $10,000 reward for clues. As days went on, internet rumors circulated that Cunningham's disappearance was tied to his alleged role as a flu vaccine whistle-blower. The rumors were debunked by police and his family.
The CDC's director in mid-March issued a statement denying that Cunningham hadn't gotten a promotion and noting that he'd been promoted in July. Atlanta police responded by doubling down on their version of events, citing the CDC as the source of the information.
The case perplexed investigators because Cunningham's keys, cell phone, credit cards, debit cards, wallet and all forms of identification were found in his house, along with his beloved dog.
In announcing that his body had been found, authorities offered no hint about why he disappeared.
Co-workers told authorities that Cunningham had been "obviously disappointed" on the morning of February 12, when he learned why he wasn't getting the promotion he'd hoped for, police have said. He left work quickly, saying he felt ill, they said.
Earlier that morning, at 5:21 a.m., Cunningham's mother had received a text message from him, she has said. "Are you awake?" her son asked. But her phone was on silent mode. "I wish I had that opportunity to answer that text," she said later.
Cunningham also called his mother at 9:12 a.m. that day, but she did not answer, Atlanta police have said. He did not leave a message.
'This is extremely hard'
Cunningham was a highly respected epidemiologist at the CDC, having risen through the ranks to become a team leader in the US Public Health Service Commissioned Corps. He earned a spot last year in the Atlanta Business Chronicle's 40 Under 40 list, a who's who of the city's young standouts.
With more than 16 years of experience in public health, he'd co-authored 28 publications on topics ranging from sleep deprivation to pulmonary disease, with a special focus on how health issues affect minorities. He worked on public health emergencies including Superstorm Sandy, the Ebola outbreak and the Zika virus.
Friends said Cunningham was smart and caring, with a big grin and big hugs to match.
Fliers circulated across Atlanta in the weeks after he disappeared. They showed his magnetic smile and urged anyone with information to call 911.
Cunningham's parents, Tia and Terrell Cunningham, said they shared a worrisome series of text messages and a phone call with their son on the evening of February 11.
"We've shared that with the detectives, and we've kept that as a private matter," his father said. "As a parent, you have indicators when things are just not right with your child, and that was the case."
When they arrived at his house a few days later, Cunningham's parents said, they knew something was wrong because his Tibetan spaniel was unattended. The dog, known as Bo, had twice accompanied Cunningham to Harvard, where he earned his master's and doctoral degrees.
Four times since their son went missing, Cunningham's parents have been told that a body had been found. Each time, they felt heart-wrenching agony, they said, only to learn it wasn't their son.
"It takes you to a place that the light is not shining in," Terrell Cunningham said. "I won't call it a dark place, but they are lows. This is extremely hard."