Updated 8:27 PM ET
(CBS/AP) BEAN STATION, Tenn. - Three children were electrocuted in separate incidents in Tennessee and Missouri on Wednesday.
A sheriff in East Tennessee now says one boy swimming in a marina at Cherokee Lake was electrocuted and a second one was revived on a life flight out of the area.
Originally police reported that both boys had been killed.
According to CBS News affiliate WVLT Knoxville, Jeffrey Atkins, Grainger County EMA director, said that four children were swimming between house boats. A woman witnessed two of the children appearing unconscious. As she tried to help, the woman felt a surge and retreated.
Grainger County Sheriff Scott Layel tells the station that the boy who died was 10 years old and the revived boy is 11.
The sheriff's office says it happened around 2:15 p.m. near the German Creek Marina in Bean Station. Police say an additional six to eight people were taken to the hospital in Morristown to be checked out.
The marina has been evacuated as authorities conduct their investigation.
Meanwhile, two Missouri children have died after coming into contact with electricity while swimming at the Lake of the Ozarks on the Fourth of July.
The Missouri State Highway Patrol identified them as 13-year-old Alexandra Anderson and her 8-year-old brother Brayden, of Ashland.
The Patrol says the children were swimming near the 6.5 mile marker in the Gravois Arm of the lake when they were electrocuted by an "unknown source of electricity" just after noon Wednesday.
KOLR-TV reports several adults at the scene removed the children from the water and performed CPR until medical crews arrived.
The children were taken to an area hospital, where doctors pronounced them dead.