Otto Warmbier’s death and the events in North Korea that led up to it remain a mystery.

North Korean officials said that during his 17 months in detention for ‘‘hostile acts against the state,’’ Warmbier had contracted botulism, was given a sleeping pill, and never woke up.

Last week, after nearly a year and a half in captivity, the University of Virginia student was brought home to Ohio in a coma. Doctors there said Warmbier had extensive loss of brain tissue and had suffered a severe neurological injury. Warmbier died Monday, six days after being flown back to the United States.

What led to Warmbier’s death? And will an autopsy be able to provide answers?

Experts say postmortem examinations can be illuminating, but the amount of time that has passed since Warmbier fell into a coma may limit what pathologists would be able to find.

Werner Spitz, a forensic pathologist who has worked on numerous high-profile cause-of-death investigations, said he is not very hopeful that Warmbier’s autopsy will be able to shed light on what happened to him, given how long his body has had to erase the evidence.

‘‘After a year of this fellow being unconscious, it is a futile effort,’’ said Spitz, who worked as a medical examiner in Baltimore and Detroit and is now a professor of pathology at Wayne State University School of Medicine.

Bruises, cuts, and other superficial markings on the skin would be among the first to fade, likely leaving behind no trace that they were ever there. Damage to bones or organs might show scars, but it would be almost impossible to tell how long ago they occurred. If Warmbier had been arrested or otherwise mishandled by North Korean security officials in such a way that it affected his ability to breathe, Spitz said, ‘‘it will not show at all.’’

One exam that may provide a hint of what happened will give a closer look at the brain.

‘‘Certain areas of the brain are more susceptible to oxygen deprivation than others. When those areas are affected, that tells you a lot about what happened in the past,’’ said Spitz, whose past cases included the deaths of John F. Kennedy and Nicole Brown Simpson.