We showed him the video and these are his big takeaways.
"Seems to be distracted with the phone and that could be a ploy to not draw attention to themselves," he says. "It looks like a casual stroll not like someone who's not nervous or someone who's done something wrong. My observation is he doesn't appear to be going to point A to point B with a purpose."
Purpose is exactly what Mullan says the killer did before the murders. Meaning just because his victims appear to be random, doesn't mean the killer acted on pure impulse.
"Either surveillance the suspect or the location or both it's highly likely even the lone wolf or terrorist act they usually case the joint," he says.