Officers found the three students when they responded to a report of a shooting at a house near the university just before 1 a.m. local time Tuesday, The Baltimore Sun reported.
Officer Nicole Hubbard said a preliminary investigation indicated one of the roommates started a small fire in the basement of the single-family home and all three went outside.
Police believe the student who started the fire fatally shot one of his roommates and injured the second roommate when he tried to flee, the Washington Post reported.
The suspect then went to the back of the house where he turned the gun on himself.
Names of the students have not been released pending notification of their families.
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