ULSTER COUNTY, N.Y. -- Two skydivers are dead after a jump goes wrong.

Plattekill police say instructor Alexander Chulsky, 25, of Brooklyn, was doing a tandem jump with David Windker, 42, of Chappaqua, around 4 p.m. Friday.

Police aren't sure what caused them to plummet to the ground, but witnesses say it looked to be a parachute malfunction.

The two came down near Hurds Farm on Route 32 in Modena.

Police say Skydive the Ranch in Gardener organized the jump.

The FAA has been notified of the incident.