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 white man, about 5'11" weighing more than 170 lbs with combed greasy brown hair, 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 a jail with a two-word name, in either Colorado or Montana (a police officer later inferred he had been referring to a jail in Deer Lodge, Montana), where he had killed a guard and subsequently stolen a car, explaining that he now needed their car and money to go to Mexico, as the vehicle he had been driving was "too hot". 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 this event to be a weird robbery, but the man drew a knife and stabbed them both repeatedly, reportedly laughing as he stabbed Shepard 24 times. 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. "