HOUSTON -- Officials of a downtown hospital are investigating the death of a surgical resident who was decapitated in an elevator mishap.

Christus St. Joseph Hospital may release additional information about Hitoshi Nikaidoh's death after a closed briefing Monday, said hospital spokeswoman India Chumney Hancock.

Nikaidoh, 35, of Dallas, was stepping into a second-floor elevator about 9:30 a.m. Saturday when the doors suddenly closed, pinning his shoulders. His head was severed when the elevator car moved upward. A female hospital employee witnessed the accident and spent about 20 minutes trapped inside the malfunctioning elevator until firefighters were able to rescue her.

The traumatized employee who witnessed the death was taken to the hospital's emergency room for treatment of shock, but was released later that day, said Hancock.

Photographs and measurements at the elevator by Houston police crime scene specialists were passed to Harris County medical examiners who continued conducting their inquiry into the accident. The entire elevator bank where Nikaidoh was killed was pulled from operation, but St. Joseph Hospital officials said the decision won't affect patient services.

The University of Texas Health Science Center's Dr. Margaret McNeese taught Nikaidoh for four years throughout medical school.

"He was a remarkable individual. He was one of the few students in all of my years here that I never saw him complain, without a smile on his face and any activity, regardless of how small or insignificant it might have seemed, he gladly took it on and did it to its full extent," McNeese said.

Nikaidoh graduated in 2003 from the University of Texas-Houston Medical School.

Kone Inc., the company responsible for servicing the elevator, gave a statement Monday that said, "We are extremely concerned about this incident, and our hearts go out to the family of Dr. Hitoshi Nikaidoh. We are working closely with the hospital and local authorities to determine the exact cause of this incident."

"The elevator bank was immediately shut down and remains out of service indefinitely," hospital spokeswoman India Hancock said. "All of us at St. Joseph Cristus Hospital are deeply, deeply saddened by the tragic death of Dr. Nikaidoh."

The hospital will hold a memorial service on campus following the family's memorial service.

Police said earlier that maintenance crews had worked on the elevators during the past week.

Elevators and escalators kill about 30 and injure about 17,100 people each year in the United States, according to data from the U.S. Bureau of Labor Statistics' Census of Fatal Occupational Injuries 1992-1998 and the Consumer Product Safety Commission.