The Coast Guard on Saturday said it was still searching for three passengers, including an adult and two children, after a boat capsized on the St. Johns River in Jacksonville, Florida, near Goat Island, leaving one person dead.

Around 7 p.m. Friday, Coast Guard Sector Jacksonville received an alert of a capsized 18-foot vessel with four people atop the overturned boat and four others trapped underneath. 

The four people on top of the boat were rescued. None of the passengers were wearing life jackets, the Coast Guard said. 

A Coast Guard member searches the St. Johns River Saturday for three missing boaters after their boat overturned in Jacksonville, Fla. (U.S. Coast Guard)

“At this point, we have found one person from the missing, and they are deceased,” Jacksonville Fire Rescue Department Capt. Eric Prosswimmer told reporters late Friday. “It’s a really unfortunate situation, and our hearts go out to all the family members.”

Officials haven’t release the age of the person who died. 

A Coast Guard boat searches the St. Johns River in Jacksonville, Fla.  (U.S. Coast Guard)

The cause of the capsizing is under investigation. 

Fox News Digital has reached out to the Jacksonville Fire Rescue Department.