Father and daughter drown as strangers try to save them after van plunges into canal

(INSIDE EDITION) - Despite the best efforts of strangers who frantically tried to help, an elderly man and his daughter drowned after their van plunged into a Florida lagoon.

Carol Hayden, 64, and her father, Eugene, 88, perished as their minivan sunk lower and lower while strangers plunged into the water in a desperate effort to free them.

"They were frozen with fear, but I'd like the family to know they certainly did everything they could to get out," one of the good Samaritans, Tim Cobb of Venice, told local reporters at the tragedy's site.

Cell phone video shows a police boat arriving as the white van went down hood-first into the intracoastal waves. Another craft hovered nearby and men jumped from it, swimming toward the sinking minivan.

One man managed to shatter a rear driver's side window with a hammer and hoisted his head and shoulders in, but was unable to reach the driver.

"I gave them the 'roll down the windows' motion and they just shook their heads," Cobb said. "They couldn't get the windows down.''

Water pressure against the van's doors prevented them from opening, he said.

The victims lived at a nearby retirement community and were well-known there, police said.

Residents said both appeared in good spirits Monday in the hours before their vehicle appeared to drive straight into the water, according to witnesses. The woman, who was driving, hit a sign, then reversed and shot forward, plunging off a jetty.

Police are investigating the incident.