His investigation into drug dealing in London’s prisons showed there was ongoing corrupt guard involvement in the criminality. Zak had to develop contacts currently inside prison and faced constant obstruction from authorities. Calls were cut off and inmates became suddenly unreachable, many others got cold feet. Sources with experience running drug smuggling operations also had to be found and convinced to talk. In the course of his reporting, Zak uncovered evidence of a drug dealing conspiracy operating over social media. The material he gathered was delivered to and investigated by police. It also prompted action from a law firm whose letterhead was being used to smuggle drugs and helped Snapchat address the fact its platform was being used to connect buyers and sellers. When Zak learned of a local authority housing provider using social service reports as a method to stop families complaining about terrible housing conditions he had a hunch it wasn’t an isolated case. A topic almost untouched by media, charities or anyone who might have advocated for the families, Zak had few obvious starting points for sourcing other examples. But, through exhaustive door-knocking and online network building, Zak found an array of similar cases that proved this was a method multiple authority figures were using. The result was a pioneering piece that challenged the actions of powerful public bodies on behalf of a vulnerable group. The article had a positive impact on the individual cases mentioned too, prompting action from the local authorities to address the issues raised. When the IOPC revealed allegations of serious misconduct by police officers at Charing Cross station Zak dug deeper to find out how far the issues went. Within hours of the news breaking, he tracked down an ex-staff member who’d witnessed even more shocking behaviour by policemen at the station. The revelations in Zak’s article showed how longstanding the culture of misogyny at this branch of the Metropolitan Police was and raised previously unheard concerns about the exploitation of sex workers. The ex-officer's claims are now being investigated by IOPC and were covered by a host of national publications.