SAN FRANCISCO -- BART officials are calling the death of a man crushed to death in an elevator shaft at one of its San Francisco stations "upsetting and disturbing," and said they have as many questions as answers about what happened.

The man's body was discovered Sunday about 9:35 p.m. after a person riding the elevator from the BART platform to the concourse level at the Montgomery Street station called the station agent to report the elevator had stopped, BART spokeswoman Alicia Trost said.

That person was rescued, but rescue personnel discovered the body of a man in the shaft, Trost said. That man appeared to be crushed and was pronounced dead at the scene at 10:04 p.m., Trost said.

Police needed more than two hours to remove the body, finally doing so about 12:15 a.m. Monday, Trost said.

The dead man's identity was withheld pending the notification of his relatives.

The person who was stuck in the elevator told rescue personnel that he was riding the elevator when he heard a "crunching sound" in tandem with a scream as the elevator stalled, Trost said. The dead man had some personal belongings on the top of the elevator shaft, but BART officials stopped short of saying whether they were sure the man was living there.

"We've never heard of a case like this," Trost said. "Obviously, the circumstances surrounding this are upsetting and disturbing. We're trying to get details on why he was up there, and how he got there."

Trost said the elevator shaft was not accessible at street level, but that BART has ventilation shafts that lead to the elevator shafts. BART officials said they checked those shafts Monday and that they are secured.

"To have someone inside a shaft, that's unusual and disturbing," Trost said, adding that it's unclear how the person got there or how long he may have made a home in the shaft. "We need to get those questions answered as quickly as we can."

A hatch door in the elevator also could be used to get in the shaft, but Trost said a person likely would need a boost from someone or something else to get through it.

State inspectors will examine the elevator to make sure it's safe before it is open to the public again, Trost said. BART trains continued to run through the Montgomery Street station during the investigation and were not delayed. The elevator remained closed Monday, and Trost said BART hopes it will be back in service by March 20.

Contact Rick Hurd at rhurd@bayareanewsgroup.com and follow him at Twitter.com/3rdERH.