DES MOINES, Wash. - An 86-year-old woman and her dog drowned after the car she was riding in plunged into the water at Des Moines Marina late Friday night.

Police and fire officials said the woman and a 76-year-old man were in the parking lot of the marina when the man stepped on the gas pedal instead of the brakes, causing the SUV to drive off of the road, crash through a railing and plunge into the Puget Sound.

Several people who had witnessed the incident rushed over to help.

"I wasn't just going to stand there, so I jumped into the water," said Stevie Kokipa.

By the time Kokipa reached the car, several others had pulled out the man from the car through the open driver's door window. But as water began rushing in, the car began to sink too quickly for anyone to react.

"And I put my hand on the door and it (the car) started to go down," said Kokipa.

The car sank to the bottom, about 12 feet below the surface.

Crews from Renton's Water Rescue Team arrived at the scene shortly after 8:45 p.m. and took over. By the time rescuers got the woman out of the water, she had been under for 28 minutes and was unconscious. Medics performed CPR, but she could not be resuscitated.

She was pronounced dead at the scene.

"This water is very cold, and so the conditions were not safe," said Kendra Kay with South King Fire and Rescue.

The couple's dog, which was also in the car at the time, also drowned.

The man was taken to a nearby hospital, where he was treated for potential hypothermia. He is expected to be OK.

The couple's names were not released.