I was out boating with some friends last Sunday, June 26, on Lake Washington and dropped my GoPro into the lake. It was close to shore right near the Magnusson Park Boat Launch. Maybe 100 meters northeast of the launch deck. My guess at the approximate coordinates are Lat: 47.678010, Long: -122.247229. According to our depth finder it was only about 35 feet in depth, too deep and murky for me to free dive. I know this is a complete shot in the dark, but If anyone is planning on taking a dive near there soon, I would gladly offer a reward. I have hours of precious family footage on there.
It is a GoPro Hero 4 with a hand stick attached.
Thank you to anyone who shows interest!