David Earl Thornton was a UC Davis senior declared as a biological sciences major expected to graduate some time in 2001. Campus officials in the Division of Biological Sciences describe him as "leaning toward evolution and ecology as an emphasis in biological sciences." From his first year as a freshman, Thornton excelled, his teachers remember. As of yesterday, he had a cumulative 3.36 grade point average. Thornton enrolled in the fall of 1997 in the Davis Honors Challenge, a campuswide program for highly motivated students interested in enhancing their education through special courses, closer contact with faculty and dynamic interaction with academic peers. Thornton completed his first year in the program. Teaching assistant Mark Renz, who assisted with Biological Sciences 1C last fall, recalls Thornton as an "incredibly bright and intelligent student who worked very well independently with little assistance." Thornton had been employed since March 1999 at the ASUCD (Associated Students of UC Davis) Campus Copies service in the Memorial Union. His manager, Randy Rubiales, said he saw Thornton yesterday, and recalls him as a "great guy. He was someone you could count on, and a fun guy to be around." He was a member of Phi Delta Theta fraternity. Thornton is from Fresno and had turned 21 yesterday.