That's not the point. What the police said, when there's a mass shooter at large and a shelter in place order, was "We have no idea who did this, call with tips." What they did not say was "We have identified persons of interest that we are seeking to talk to in relation to these incidents."
Remember that very early on, reporting was that there was a third shooting location at a WalMart distribution center (which seems to be off the table now, not sure why), and that there could be multiple perpetrators. They knew who they needed to talk to, and they chose not to ease the public concern at all by communicating that.