The University of Colorado says it has asked non-essential personnel to go home in three of its research buildings at the Anschultz Medical campus in Aurora.
The move comes after news that the suspect in a shooting at an Aurora movie theater that killed 12 people was a student at CU Denver.
The suspect, James Holmes, was studying for a PhD in neuroscience at the university until recently.
CU-Denver confirmed that Holmes took classes for one year and was in the process of withdrawing from the graduate program.
As a precaution, search dogs are being brought in to look for anything suspicions, said spokeswoman Erika Matich.
Matich said there is no reason to believe there's any danger or threat. Officials just want be cautions.
Holmes was arrested outside the theater with several guns, said Aurora police.