According to a new filing by prosecutors in the Rex Heuermann case, a Suffolk detective said one of Heuermann’s phones “has had significant contacts with at least sixty (60) prostitutes.”

The defendant’s internet searches allegedly included: “why hasn’t the Long Island serial killer been caught” and “why could law enforcement not trace the calls made by the Long Island serial killer.”

The court filing cites a Suffolk detective who said there was clear evidence that Heuermann “was a sexual sadist” and that there were “significant searches for pornography related to bindings, torture, rape, snuff videos, crying, bruised and impaled women and/or girls…”

It’s also alleged the defendant searched for images of victims’ family members “mourning the deceased.”

Heuermann has been charged in connection with seven murders.

He pleaded not guilty.

He’s due back in court March 17.