KEY LARGO, Fla. -

A Georgia man has died while snorkeling off Key Largo.

Monroe County Sheriff's Office spokeswoman Becky Herrin said John Marshall, 71, of Johns Creek, Georgia, was with nine others while snorkeling off a 25-foot private boat Thursday afternoon.

Witnesses told deputies they saw Marshall on his way back to the boat. When they saw him again he was face down in the water.

Herrin said witnesses pulled him into the boat, and another boat with a doctor on board pulled up. That doctor began CPR.

Authorities were called and brought Marshall to the marina, where he was pronounced dead.

One day earlier, a New Jersey man died after a diving trip with his teenage children off Key Largo.

Gary Lanier, 45, of Kenvil, New Jersey, was pronounced dead Wednesday.

Autopsies are being performed to determine the causes of death.