Employees at the Hatfield campus said they believed the man behind the murder of Johan de Beer knew how to bypass security at the institution.
The 64-year-old De Beer, a retired agricultural science lecturer, was maintenance manager at the university when he was found dead in a toilet cubicle in the Musaion building in the early hours of Wednesday.
His hands were tied behind his back and a plastic bag was tied over his head. A post-mortem showed that the grandfather had died as a result of suffocation.