Police turned over to prosecutors Monday their case against several employees of elevator and escalator manufacturer Schindler Elevator K.K., accusing them of professional negligence in the death of a 16-year-old Tokyo boy in 2006.

The elevator maker failed to take proper safety measures and mishandled information about a similar accident in the past, investigative sources alleged. Tokyo police had earlier believed it would be difficult to build a case over the accident because the elevator itself had no defects.

The police also turned over to prosecutors their case against several people employed by maintenance company SEC Elevator Co. over the same accident due to insufficient safety checks on the elevator.

Hirosuke Ichikawa, a second-year high school student, was killed when the elevator he was backing out of suddenly went up with its doors open and he was crushed between the elevator floor and the upper door frame.

Schindler, a wholly owned Japan unit of Swiss elevator maker Schindler Holdings Ltd., was in charge of maintenance on the elevator from its installation in April 1998 to March 2005. After another firm took over the maintenance checks, SEC became responsible for checking it from April 2006. The accident occurred two months later.