JENNER, Calif. -- Investigators in Sonoma County are hoping reward money will provide them with some leads into the shooting deaths of two camp counselors last week.

A private foundation has posted a $10,000 reward for information into the murders of 23-year-old Lindsay Cutshall and 26-year-old Jason Allen.

The two were shot to death as they slept on a secluded beach near Jenner.

Meanwhile, investigators have cleared a Wisconsin man they wanted to talk to about the case. Nicholas Edward Scarseth, 21, called police after it was announced that he was "potential witness" in the killings. He was interviewed Tuesday, passed a polygraph test and was then released in what his parents say was a case of mistaken identity

Authorities returned Wednesday to a foggy Sonoma State Park to resume their investigation. Deputies closed the beach and blocked the trail leading to where the campers were killed.

Photos Of Couple Released

Authorities also tried to ease the fears of nearby residents with a nighttime briefing at a community center attended by more than 80 people. Many appeared to be unhappy about the slow-moving investigation.

"We thought we were in a cocoon here, isolated and insulated from the rest of the world. Then this happened in our back yard," said John Chyle, a longtime resident of Jenner.

Police have seized the surveillance video from the general store in town and are using helicopters at night to do thermal imaging along the beach to try to find any camp sites.

Two people reported hearing gun shots on the night of Aug. 17 at about 8:30 p.m. and 8:50 p.m. Cutshall, of Fresno, Ohio, and Allen, of Zeeland, Mich., were reported missing Aug. 16 after they failed to show up at a Christian adventure camp in Coloma, about 40 miles east of Sacramento.

Also Wednesday, authorities released photos of the couple believed to have been taken just a day or two before they were killed.