The Experts responded by issuing a statement that the company was disappointed with Hewlett-Packard's decision.
"The Experts is disappointed in H-P's decision, as we have continued to meet all of our contractual obligations. The Experts had no greater insight into Alexis' mental health than H-P, particularly given that an H-P site manager closely supervised him, including during the events in Rhode Island," the statement said.
At the Pentagon, Deputy Defense Secretary Ash Carter said the department will review base safety procedures and the security clearance process.
"Bottom line is, we need to know how an employee was able to bring a weapon and ammunition onto a DoD installation, and how warning flags were either missed, ignored or not addressed in a timely manner," Carter said.
Navy Secretary Ray Mabus has recommended that the department require that all police reports — not just arrests or convictions — be included in background checks.
Associated Press writers Lolita C. Baldor and Jack Gillum contributed to this report.