On September 27, 1969, Pacific Union College students Bryan Hartnell and Cecelia Shepard were picnicking at Lake Berryessa on a small island connected by a sand spit to Twin Oak Ridge. A man approached them wearing a black executioner's-type hood with clip-on sunglasses over the eye-holes and a bib-like device on his chest that had a white 3"x3" cross-circle symbol on it. He approached them with a gun, which Hartnell believed to be a . 45. The hooded man claimed to be an escaped convict from Deer Lodge, Montana, where he had killed a guard and stolen a car, explaining that he needed their car and money to go to Mexico. He had brought precut lengths of plastic clothesline and told Shepard to tie up Hartnell, before he tied her up. The killer checked, and tightened Hartnell's bonds after discovering Shepard had bound Hartnell's hands loosely. Hartnell initially believed it to be a weird robbery, but the man drew a knife and stabbed them both repeatedly. The killer then hiked 500 yards back up to Knoxville Road, drew the cross-circle symbol on Hartnell's car door with a black felt-tip pen, and wrote beneath it: "Vallejo/12-20-68/7-4-69/Sept 27–69–6:30/by knife. "