He used explosive devices to kill others and, eventually, himself. In a 25-minute recording, he detailed the weapons he had made and confessed to the crimes. He terrorized the residents of Austin, Tex.

But law enforcement officials said that Mark Conditt was not a terrorist.

“What I can tell you having listened to that recording, he does not at all mention anything about terrorism nor does he mention anything about hate,” said Brian Manley, the Austin police chief, on Wednesday. “It is the outcry of a very challenged young man talking about challenges in his personal life that led him to this point.”

The statement befuddled citizens in Texas and elsewhere who presume that any killer is “challenged” and has enormous personal problems. It also angered people who felt that by portraying Mr. Conditt as a troubled young man who lost his way, the police positioned him as an empathetic figure, which they argued would not have been done had he not been white.

As often happens after a high-profile act of seemingly indiscriminate violence, people quickly began to question why law enforcement uses the term terrorist in some instances and not others.