KISSIMMEE, Fla. (WHDH) — Three family members from Massachusetts died in a chain-reaction crash near Walt Disney World on Tuesday evening.

Julie Smith, 41, and her 5-year-old daughter, Scarlett, both of Whitman, succumbed to their injuries after a truck rear-ended their rental van on State Road 429 in Kissimmee, Florida, causing it to roll over right when traffic was starting to slow down, according to Florida Highway Patrol Lt. Kim Montes.

The young girl’s maternal grandmother, 76-year-old Josephine Fay, of South Weymouth, was also pronounced dead.

“We don’t know why this truck didn’t stop yet but clearly that truck is at fault for rear-ending the van and we just got to sort everything else out,” Montes said.

A total of eight family members from Massachusetts were inside the rental van at the time of the crash.

The 5-year-old’s twin sister and her 10-year-old sister were not injured, however, her 11-year-old brother was found unresponsive and in critical condition, Montes added. Her father and maternal grandfather are in stable condition at a hospital.

“We have our victim advocate and other social workers over at the hospital helping this group of people get the help that they need and then also relay the bad news to them,” Montes said.

Authorities say the pickup truck also hit two other vehicles but those drivers were not seriously hurt.

“It’s a reminder for drivers: traffic can stop suddenly,” Montes added.

Whitman school officials say grief counselors will be made available for students and staff of the Whitman-Hanson community.

“This is a tragedy, and I believe I express the sentiments of all families, students and employees of the Whitman-Hanson Regional School District in saying that we mourn together during this incredibly difficult time,” Superintendent Jeffrey Szymaniak said. “I encourage all families to have honest and open conversations with their children. We have activated all the resources at our disposal, and we will come together as a community to support each other and support our students who have suffered this terrible loss.”

The crash remains under investigation.

This is a developing story; stay with 7NEWS on-air and online for the latest updates.

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