About 3,000 students, faculty and staff gathered in the Hytche Athletic Center on the Princess Anne campus for the meeting, where school officials and campus police attempted to allay concerns about security.
He later said police had spoken with "persons of interest" but declined to elaborate, saying, "There's nothing to confirm because no one has been arrested."
St. Clair, 21, of Severn, was fatally stabbed near the school's University Terrace residence hall on Saturday night as the school concluded its homecoming week. The victim's brother, Isaiah St. Clair, has said he and a friend, Tre Hardy, were driving with Edmond through campus when they encountered three men in the road who wouldn't move. Edmond St. Clair got out to talk to the men and was stabbed in the heart, his brother said.
"I stand before you a different person than I was three days ago," UMES President Juliette B. Bell told students at the Hytche center. "We are all different now. … We are shocked, and pained, and angry and sad."
Bell pledged to take steps to ensure campus safety at the 4,000-student university. UMES spokesman Bill Robinson said that as of Sunday, campus police had gone from 8-hour to 12-hour shifts, which he said "ostensibly doubles the number of patrol officers we have on campus at any one time." He said the shifts will remain in place indefinitely.
Robinson has said campus police were "fully deployed" during homecoming and had assistance from state police, with Princess Anne and Somerset County law enforcement on call as well.
Isaiah St. Clair said he knelt next to his brother on the sidewalk and held the wound while Hardy ran to flag down a campus police officer in a nearby patrol car. At the campus meeting, officials distributed a flier with five blurred security camera images of cars and individuals near University Terrace hall.
State police are offering a reward of up to $2,000 for information leading to an arrest and conviction.
Collins said after the assembly that officials believe there may be multiple witnesses to the stabbing because a campus security officer, who was in a nearby security booth, heard shouts from St. Clair's brother and saw "20 to 30 students" running from the direction of the incident.
"Obviously they were there when it happened. The body was there, and they were running from it," Collins said. "And the cameras show images of people and vehicles passing, so we know there are potential witnesses."
He said police don't know if the suspects — described only as three black men in the late teens or 20s — are students.
"Since it was homecoming, it's hard to say," he said. "We had so many people, friends of students on campus, alumni, and I'm sure there were some local people here as well."
The only UMES student who spoke at the assembly was student government president Shana Washington, who said the group will hold a vigil on campus Wednesday at 11 a.m. Robinson said Wednesday classes have been canceled for "a day of reflection."
After the assembly, a campus fraternity held a prayer circle outside the athletic center. As they left Tuesday's gathering, some students said the campus was still in shock.
"It's been a tough time for everyone," said junior Myisha Flannary, of Easton. "We're just trying to deal with everything. Everyone is shocked. Violence doesn't happen on this campus at all."
Senior Akil Stewart, from Queens, N.Y., said he hopes the attacker is found and added, "I hope we all learn from this."
Bell told students that UMES remains, "a vibrant community," and added, "We are smart, we are resilient, we are tough, we are powerful. We are not victims."
St. Clair's was the second death this past weekend involving UMES. On Monday, Princess Anne police notified the school that Dickson Muiruri, a former UMES student who left the university in December, had been found dead in his off-campus residence.
Princess Anne Police Chief Scott Keller said Muiruri is believed to have died around 2 a.m. Sunday. The cause of death had not been determined pending an autopsy, he said.