“The techniques would include cyber-searches of language that mass-casualty shooters have used in e-mails and Internet postings,” Mr. Kelly said in a statement. “The goal would be to identify the shooter in cyberspace, engage him there and intervene, possibly using an undercover to get close, and take him into custody or otherwise disrupt his plans.”…

Mr. Browne said the potential tactics included creating an algorithm that would search online “for terms used by active shooters in the past that may be an indicator of future intentions.”

Mr. Kelly said the technique was similar to those being used to spot terrorists’ chatter online. The new searches would target “apolitical or deranged killers before they become active shooters,” he said.