Retired University of California-Davis sociology professor John Finley Scott, 72, has been missing for three months. While his whereabouts remain unknown, evidence found at his Davis, Calif., home indicates foul play might have occurred.

Scott was last seen June 1 when he rode his bike from his ranch house to attend a party on campus, during which he was said to have been happy and smiling for photos.

He sent an e-mail to a friend on June 3, but has not been heard from or seen since. Friends reported Scott missing June 11.

Upon searching his home, Yolo County (Calif.) sheriff’s investigators found blood spatters indicative of severe injury. Specific information regarding the amount and location of the blood has not been released.

Despite the evidence, Yolo County Sheriff’s Capt. Larry Cecchettini said Scott’s disappearance remains a missing persons case, not a homicide investigation.

We have no body, but the family is prepared for the worst news, he said in an interview with The Sacramento (Calif.) Bee. Significant physical evidence was found that leads us to believe he sustained injury.

After initial investigations of Scott’s house, a man allegedly stole a trailer from the property. The trailer was later found empty in a field, and the thief, whose name authorities declined to release, was arrested for a parole violation. He has not been ruled out as a suspect in Scott’s disappearance but has not been charged in the case, authorities said.

Recent activity in one of Scott’s bank accounts is also under investigation.

Scott has a sister and two nieces but no children. He is known as a pioneer in the cycling world, having virtually invented the mountain bike. He also successfully lobbied the California Legislature to apply vehicle instead of pedestrian traffic laws to bikes in the 1970s.

As a former double-deck bus driver, Scott was interested in studying the impact of Unitrans buses on the popularity of traveling by bike among students, said friend John Allen on a bicycling enthusiast Web site.

Scott authored the 237-page 1971 sociology textbook Internalization of Norms: A Sociological Theory of Moral Commitment, the 1967 text The American College Sorority: Its Role in Class and Ethnic Endogamy and the 1966 28-page pamphlet So You’re Going to College!