The National Transportation Safety Board on Friday reduced its team of investigators at the site of a plane crash that killed 25 people and said it still hadn't a clue about what caused the crash.

United Flight 585 crashed Sunday while on normal landing approach, plunging suddenly for unknown reasons and crashing nose first into a park three miles from the Colorado Springs airport runway. Twenty passengers and five crew members died.The NTSB said about one-fourth of the 60 investigators on site will remain to reassemble the jet from wreckage, using a nearby rented warehouse, and to continue gathering information.