She also confirmed that the suspect has been identified as Gary Martin, CNN reported.
Police officials believe that the shooter was an employee at The Henry Pratt Company building, where the incident took place, although the motive is yet to be ascertained.
Two federal law enforcement officials told CNN that the gunman is dead.
Earlier, there were reports on social media that the suspect was apprehended and sent to custody.
Thanking law enforcement personnel for their 'selfless act', Ziman further informed that six police officers sustained injuries during the shooting and are being treated at local hospitals in Aurora.
US President Donald Trump, who was briefed on the incident, expressed his condolences to the victims and their families affected in the shooting.
'Great job by law enforcement in Aurora, Illinois. Heartfelt condolences to all of the victims and their families. America is with you!' Trump wrote on his Twitter handle.
Friday's incident comes barely a day after the US marked the first anniversary of the mass shooting that took place in Marjory Stoneman Douglas High School in Parkland, Florida, which claimed 17 lives.
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