The investigation continued Monday after a small plane crashed in North Salem, New York, on its way to Danbury Airport Thursday.

A police car guarded the site of the deadly plane crash Monday morning. The 1971 Beechcraft Bonanza went down in the Titicus Reservoir. 

South Salem couple Val and Tao Horsa are believed to have been killed in the crash. Human remains were recovered and sent to the Westchester Medical Center for identification. Family members have said that the couple was on the plane.

The Horsas owned a popular Thai restaurant in Danbury.

The New York City Department of Environmental Protection said police divers had been searching the reservoir, using sonar to check the water for plane debris. Investigators had also searched the banks of the reservoir for wreckage. 

Searchers worked through the weekend and they believe they found parts of the plane.

Officials say the water is very cold, so divers can only go down for a certain amount of time.

DEP officials say once they recover most of the wreckage, the National Transportation Safety Board will investigate the cause of the crash.