Just because some politician claimed that it's tech's people responsibility to fix their flaws, it does not make it true.
It's repetitive, but the police did have all the information they needed to go after such people even before the murdering. What does the GP want? A machine that queries the news from the day after tomorrow? (Because tomorrow won't do - the police had warning that it would happen at the previous day.)
If the Paris police had all the information they needed to go after such people, but didn't, that's the technical problem that really needs solved, not an encryption backdoor.
Better data organization tools are another (a family member is studying forensic science and has done internships with large-ish police departments that still largely use printed and hand-written documents to manage cases)
But that's my point. I haven't done much thinking on this either, so I can't see around the corners of time to see what it could be. But just more yelling back and forth about encryption isn't accomplishing much.
Maybe it's not a bits and bytes technical problem, but it's technical according to the definition of the adjective, "of or relating to a particular subject, art, or craft, or its techniques." If the Paris police had the information, but were unable to properly analyze it, that's completely a technical problem.
But I still don't think this should distract from a conversation about encryption. Encryption has very importat implications for free press and privacy far outside of preventing terrorism, and it's important that it stay legal and accessible to normal people. Experts need to make their voices heard so that legal decision isn't made by people unconcerned with these important issues.