North Korea has released American college student Otto Warmbier after imprisoning him for more than a year, U.S. Secretary of State Rex Tillerson said in a surprise announcement Tuesday.

The 22-year-old Warmbier was detained on January 2, 2016 after allegedly attempting to steal a propaganda banner from his hotel in Pyongyang. He was sentenced last March to 15 years of hard labor and has been held with little word on his condition ever since.

Warmbier’s parents told the Washington Post that he’s in a coma and was being medically evacuated through a U.S. military base in Sapporo, Japan. Warmbier reportedly slipped into a coma shortly after his last public appearance in March 2016.

“Our son is coming home,” Fred Warmbier told The Washington Post. “At the moment, we’re just treating this like he’s been in an accident. We get to see our son Otto tonight.”

The Warmbier family was told that Otto came down with botulism and did not wake up after being given a sleeping pill, according to the Washington Post’s Anna Fifield. A spokesperson for the Richardson Foundation, which has been working with the Warmbier family to secure Otto’s release, confirmed the report to Vice News and said Otto’s condition is critical.

Bill Richardson, the former New Mexico governor and U.N. ambassador who has negotiated with North Korea, released a statement that said Warmbier has been in a coma for over a year and “urgently needs proper medical care in the United States. “In no uncertain terms North Korea must explain the causes of his coma,” Richardson said.

Tillerson said in a statement that Warmbier is “en route to the United States, where he will be reunited with his family,” and declined to comment further “out of respect for the privacy of Mr. Warmbier and his family.”

The release of Warmbier coincides with a visit to the North Korean capital by former NBA player Dennis Rodman, but it’s unclear whether Rodman, who has visited the reclusive nation four times before and maintains some sort of friendship with Kim Jong Un, had anything to do with securing Warmbier’s freedom. Rodman told reporters in Pyongyang after his arrival that negotiating the release of Warmbier and three other detained Americans was “not my purpose right now.”

Warmbier hails from Wyoming, Ohio (a suburb of Cincinnati), and was attending the University of Virginia when he was detained in Pyongyang, where he traveled as a tourist. North Korea released blurry surveillance footage that showed a blurry figure — allegedly Warmbier — taking a propaganda banner from an off-limits area of his hotel. Before his detainment in North Korea, Warmbier was entertaining a future in the finance industry, his parents have said.

Warmbier gave a bizarre and tearful confession where he admitted taking the banner at the behest of his church and the Z Society, a philanthropic organization at his college. North Korean state media at the time said Warmbier “was caught committing a hostile act against the state,” which it said was “tolerated and manipulated by the US government.”

After staying silent for more than a year, Warmbier’s parents recently began speaking out about their son’s case, granting interviews to Fox News and the Washington Post. They criticized Secretary of State John Kerry and the Obama administration for failing to secure his release, telling the Washington Post in April that their son “seemed to be an unwanted distraction” for the Obama administration. They said they had received no word about his condition for 16 months. They started speaking out shortly after Trump took office.

Tillerson said Tuesday that the State Department, which does not maintain formal diplomatic ties with Pyongyang, is still discussing the cases of three other detained Americans in North Korea, including two Korean-American teachers who were arrested this year.

North Korea has imprisoned numerous Americans over the years, often sentencing them to lengthy terms in prison that have rarely, if ever, been served out. Previous detainees have been freed following visits to Pyongyang by high-profile U.S. officials, including Bill Clinton, Al Gore, Jimmy Carter, and James Clapper, the former Director of National Intelligence.