What to Know Doctors say the wreckage was so shocking even the paramedics were shaken

A 10-year-old boy headed to a water park to celebrate his birthday and a former Cuomo aide were among those who died

Authorities are investigating speeding as a possible cause of the crash

A former aide to Gov. Cuomo and a 10-year-old boy heading to a water park for his birthday were among six people killed Sunday morning in a horrific multi-vehicle crash on the Long Island Expressway, police said.

The former aide, Scott Martella, 29, was driving westbound on the expressway near exit 68 in Shirley around 9:35 a.m., when an out-of-control Subaru Outback crossed over a grassy median and slammed into his Honda and a BMW, authorities said. The Outback went airborne during the crash.

Martella, the communication director for Suffolk County Executive Steve Bellone and and a former Cuomo representative in the county, was pronounced dead at the scene. His fiancee, Shelbi Thurau, was taken to a local hospital and is expected to survive her injuries, police said.

The driver of the Outback, Carmelo Pinales, 26, of Hicksville, and his sister, Patricia Pinales, 27, of Westbury, were also pronounced dead at the scene, police said.

Carmelo Pinales' 10-year-old son Christopher was taken to Stony Brook University Hospital via helicopter in critical condition but died hours later, authorities said. He was on his way to celebrate his birthday at Splish Splash.

His aunt, who was in the car and survived, had taken a Snapchat video in the vehicle minutes before the crash, relatives said.

The driver of the BMW and his three passengers, all from Westhampton, were taken to local hospitals. One occupant of the car, Isadore Adelson, 81, died late Sunday. His wife Helen, 71, died Monday at Stony Brook University Hospital.

All lanes westbound at exits 68 and 69 were closed following the accident.

Police are investigating reports that Pinales was speeding. According to the New York DMV, he has a full and valid driver's license with no suspensions or convictions.

Doctors say the wreckage was so shocking even the paramedics were shaken.

"Many say it was the worst crash they've ever seen," said James Vosswinkel of Stony Brook University Hospital.

Martella and his fiancee, his high school sweetheart, had been anticipating a bright future.

When the couple got engaged last year, Shelbi Thurau posted on her Facebook page: "Sometimes 14-year-old girls are silly. But sometimes they know just how their happily ever after is going to turn out. Scott Martella and I met in the Smithtown High School auditorium and tonight that's where we got engaged! I've never loved anyone more and I am so lucky I get to spend the rest of my life smiling alongside him."

Sunday night, Cuomo called Martella a “dedicated, beloved public servant who worked day in and day out to improve the lives of his fellow New Yorkers."

Bellone said he was "known across Long Island as a leader and a great man."