Suffolk County Police Second Squad detectives are investigating a motor vehicle crash that killed a motorist in Commack tonight.

A 74-year-old man was operating a 1989 GMC Suburban southbound when the vehicle struck a median on Larkfield Road and overturned at approximately 5:50 p.m. He was transported to South Shore University Hospital in Bay Shore where he was pronounced dead. His name is being withheld pending notification of next of kin.

Detectives are investigating whether the motorist suffered a medical emergency prior to the crash.

The vehicle was impounded for a safety check.

Detectives are asking anyone who may have witnessed the crash to call the Second Squad at 631-854-8252.