MARYSVILLE — After helping two of his children struggling to swim at Twin Lakes Park, a dad had to be helped himself by bystanders.

Firefighters say a witness dove down twice to save a man Sunday afternoon.

The Everett man, 36, was found about 30 feet offshore, in about 10 feet of water, Marysville Fire Marshal Tom Maloney said June 15.

Firefighters say the father went into the water to help his 7-year-old boy and 9-year-old girl. The father got one child out, then helped the second but encountered trouble.

“We don’t know why,” Maloney said.

Rescue crews were called about 4 p.m. They took over resuscitation efforts that had been started by people at the park.

An ambulance arrived the father and his children were taken to Providence Regional Medical Center in Everett, police Cmdr. Robb Lamoureux said. He remained hospitalized, though his condition was not made public.

The children were not injured, police said.

Maloney said life vests are available for free to use at the lakes.

“I wish people would use them,” he said.

He added he wished they had a public education person or information officer who could “get the word out.”