Philip Markoff, also known as the Craigslist Killer, evaded police for weeks despite appearing on surveillance video footage in the hotels where his victims were staying. But it wasn’t physical evidence that eventually led police to the Boston University medical student. It was a trove of cyber information – IP addresses, emails, Facebook activity – that Markoff left behind when he logged onto his computer and began browsing the web. Freelance journalist James Robinson dissects the police’s cyber-search in “Hunting the Craigslist Killer,” his recent article for the Boston Phoenix.