A call came for two planes that collided over the lake around 2:20 p.m., Higgins told CNN Sunday.
Two victims, both deceased, were recovered from the plane before sinking, Higgins said.
The remaining six victims are still unregistered, but are believed to be dead, Higgins said. They include adults and children, but no further details were available.
Investigators have not yet determined the cause of the collision or the number of victims on each aircraft, Higgins told CNN.
The planes were located in 127 feet of water by a sonar team, Higgins said, and will not be recovered on Monday or Tuesday.
One aircraft involved in the collision was a Cessna 206, Ian Gregor, spokesman for the Federal Aviation Administration told CNN.
Investigators do not yet know the brand and model of the other aircraft involved.
The FAA and the National Transportation Safety Board are investigating the collision, Gregor said.
There were several witnesses who either saw or heard the collision, or witnessed the aftermath, said Higgins, as many people were boating on the lake during the holiday weekend.