A year after graduating, Davis went off to Drexel, a 6,000-student college in Philadelphia's west end. Named for its founder, pioneering financier Anthony J. Drexel, the university has always sought to innovate.
Drexel's 1992 yearbook, the Lexerd, boasts about the school's cyber-orientation, described as crucial "because you can't live in today's society without knowing how to use a computer."
Along with Harn and DaSilva, Davis in 1992 pledged the TKE house.
"Drexel was not a big fraternity school," said Norman Leebron, who was an adjunct business professor at the school and academic adviser to the TKE house in the 1990s.
The TKE men were a "polyglot group" of business and engineering students, he said. "They didn't get into the usual trouble as fraternities that were rowdier. The Tekes seemed to be more academically oriented."
Harn and DaSilva attended the university from 1991 to 1997 but did not earn degrees. Harn studied information systems, DaSilva business administration and marketing.
Harn stood out at the fraternity for his gangly, 6-foot-3 frame, long hair worn in a ponytail and the jeans and oversized sweaters he preferred to others' preppy attire. He was also the fraternity's computer whiz, a laptop in tow, always several steps ahead of fellow computer devotees.
"He was very helpful to anyone who needed help with computer-related projects," recalled Joseph Wallace, 29, who lived next door to Harn on the fraternity's second floor.
Wallace, a computer engineer who lives in Philadelphia's Center City, remembers Harn as having a self-taught kind of intelligence. "He was independently smart - not really book smart."
As part of the university's co-op program, in which students divide the school year between a job and class, Harn worked as a computer troubleshooter at the University of Pennsylvania.
Inside the frat house, Harn and several brainy friends took turns mastering a video game in which a motley group of objects had to be strung together to solve an puzzle.
"I did level 5 and gave up," recalled David Pyne, 28, a fraternity brother whom Harn had sponsored for membership. "I think they completed the entire game - all 100 levels."
DaSilva was Harn's roommate, and their room housed the fraternity's only cat - a little black one. The two were close friends despite DaSilva's flashier style. And their well-kept room, with a couple of new couches, became a pre-party gathering spot. "Most parties ended up starting there," says Pyne, a self-employed Internet consultant outside Philadelphia.
Davis, a wisecracker who favored what one fraternity brother described as "the newest of the new" in fashion, lived across the hall. At 5-9 and a trim 140 pounds, he played club soccer.
"Derrick was pretty loud," Pyne said. "He always liked to make people laugh. He was just a funny guy, like Seinfeld is a funny guy."
The three were part of a group that went to dance clubs like The Bank, where dress-to-impress young professionals danced to techno music.
The closest they came to gambling was in the in-house football pool, according to Wallace. But another fraternity member remembers occasional trips to Atlantic City.
The fraternity continued to be a draw for Davis, who Pyne said returned periodically "to party."
'Didn't hurt anyone'