LAKE BILLY CHINOOK — The search for the body of a man who presumably drowned trying to save his son Thursday at Lake Billy Chinook will resume this morning with plans to use sonar technology, Jefferson County Sheriff Jim Adkins said.

Mark Harris, 37, died after suffering a major head injury in the water, possibly from being hit by their boat or his own ski, and it appears Gene Harris, 73, drowned after jumping in to rescue his son, Adkins said.

Search and rescue personnel recovered Mark Harris' body Thursday. Efforts to find Gene Harris' body were suspended Thursday evening, Adkins said.

A sonar device that is pulled behind a boat and used to map the bottom of the lake is scheduled to arrive from the Klamath County Sheriff's Office this morning, Adkins said. Operators of the sonar device can pick out the body from other objects like rocks and logs and use GPS to mark the spot for divers.

Both men were avid water skiers and frequented the lake, Adkins said. Mark Harris had recently bought a new ski and wanted to test it.

Adkins said several of the search and rescue officers on the scene knew Gene and Mark Harris, members of a prominent farming family in the area.

There were no witnesses to the initial incident. A man on shore about 100 yards away reported seeing a body floating in the water near a ski boat and Gene Harris swimming toward it.

The witness saw Gene Harris fight the waves, struggling to stay afloat before disappearing underwater, Adkins said.

The two were boating in or around a slalom skiing course in the Crooked River arm of the lake just north of the Southwest Jordan Road bridge, near where the river widens and flows into the lake.

About 25 search and rescue personnel from six agencies patrolled the water in eight boats, focusing on the area around the course, looking for any sign of Gene Harris' body. The small orange and yellow course buoys bobbed in the waves, the water green from algae blooms.

The murky water has proved to be the most challenging aspect of the search, Detective Starla Green said.

“The water clarity is the biggest issue," she said. “You can maybe see four or five feet deep."

Divers from the Deschutes County Search and Rescue squad were in the water Thursday evening. For the safety of the those on the water, the Sheriff's Office called off the search as daylight faded, Green said.

The water is about 120 feet deep in the area, Green estimated.

Mark Harris' body was recovered without a personal flotation device and it's unknown if Gene Harris was wearing one, Green said.

Mark and Gene Harris were the only two on the ski boat Thursday. The Sheriff's Office recovered the boat, Adkins said.

About 10 miles southwest of Madras and surrounded by towering basalt cliffs, the lake is a popular spot for anglers and recreational boaters. There are accidents every year, Green said. Thursday marked the first fatality at the lake this year, she said.

Assisting the Jefferson County Sheriff's Office and the Deschutes County Dive Team were the Oregon State Police, the Warm Springs Police Department, the Jefferson County Fire Department and the Oregon Parks and Recreation Department.