William Phillips, an employee of Jacobs Engineering Group, smuggled a revolver into the Johnson Space Centre in Houston on Friday afternoon and barricaded himself into Building 44, a warehouse that contains communications and tracking systems for Space Shuttles.
Phillips shot and killed himself and a male Nasa employee. A second person, a female co-worker, was taken hostage but escaped.
It is thought there had been some altercation between Phillips and the Nasa employee and that the killer had not intended to take a hostage.
"Our primary concern, from the moment we were notified of this event, was for our employees, Nasa personnel and other contractors in the area," said a statement from Jacobs Engineering.
"We immediately verified the location and safety of our employees who work in Building 44 and nearby facilities.
"All of our security and emergency response actions surrounding this event were under the control of, and fully coordinated with, Nasa Johnson Space Centre Security.
"We want to express our deepest sympathy for the deceased Nasa employee and his family which has suffered this tragic loss and the trauma suffered by the other employee and her family."
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