A two-vehicle crash left a man dead after roadside rescue went wrong.

A 77-year-old Vermont man was killed on Sunday afternoon while attempting to rescue a turtle on Interstate 95 in Indian River County, Florida, authorities said.

The fatal accident occurred around 4:20 p.m. on the southbound lanes of I-95, just north of Sebastian Boulevard, according to the Florida Highway Patrol.

The man was crossing the lanes when a chain-reaction crash unfolded, investigators said. A Miami woman driving a vehicle slowed down to avoid hitting the pedestrian, but a Dodge Ram pickup truck behind her failed to brake in time, authorities noted.

The pickup truck rear-ended the first vehicle, which then veered off the road, crashed through a fence and came to rest on the west side, according to authorities. The Ram continued southbound and struck the Vermont man, who was thrown to the left shoulder of the highway, officials said.

First responders pronounced the man dead at the scene, officials noted.

The driver of the Dodge Ram, identified as a 53-year-old Port St. Lucie man, and the occupants of the other vehicle -- a 44-year-old woman and her 49-year-old male passenger -- were not injured in the crash, authorities said.

The southbound lanes of I-95 were closed following the incident while authorities investigated.

It's unclear what happened to the turtle in the incident, and Florida Highway Patrol didn't immediately respond to ABC News' request for comment.