Theodore Streleski, a former graduate student at Stanford University where he bludgeoned a professor to death with a hammer in 1978, has rejected parole for the third time rather than agree to stay away from the campus. Streleski, 48, a prisoner at the Vacaville Correctional Medical Facility, again refused to sign the routine parole agreement and was returned to custody. Streleski has said he cannot promise not to kill again, and opposes restrictions on a return to Stanford. Streleski, who unsuccessfully pursued a doctorate for 19 years, said he killed the professor to protest the way Stanford treated graduate students. A state prisons spokesman said that on Sept. 8 Streleski must be released on his own terms--with no parole restrictions at all.