Otto Warmbier returns home: A timeline of the student's North Korea detainment

More than a year after he first arrived in North Korea, 22-year-old American college student Otto Warmbier returned home to Cincinnati with his parents this week after being detained in North Korea for nearly 13 months full months.

It is now known that Warmbier has been in a coma since March 2016, when he was sentenced to 15 years of hard labor after being arrested on charges of stealing an item with a propaganda slogan on it.

Click through for a timeline from Otto Warmbier's arriving in North Korea to this week's homecoming events:

Doctors have concluded that Warmbier suffered a "severe" neurological injury during the time of his imprisonment under what Warmbier's father, Fred, called the "pariah regime." North Korea blamed Warmbier's comatose state -- described by a doctor as "responsiveness wakefulness" -- on botulism, but Fred Warmbier doesn't buy it.

"We don't believe anything they (North Korea) say," said Fred Warmbier, who was wearing his son's sport coat as he discussed Otto during a Thursday press conference.

North Korea's official KCNA news agency said in a one-line report on Thursday the student was "sent back home on June 13, 2017 on humanitarian grounds according to the adjudication made on the same day by the Central Court of the DPRK."

RELATED: A look at the scene from Otto Warmbier's US arrival