A week before he was expected to give a presentation on how to hack into pacemakers, well-known hacker Barnaby Jack passed away in San Francisco last night from unknown causes.

An autopsy is currently being conducted and police have otherwise ruled out foul play, according to Reuters. He was in his mid-thirties.

Jack was considered a “white hat hacker” and worked as a researcher for security firm IOActive. He was expected to give his presentation on a lethal pacemaker hack at the Black Hat security conference on Thursday, August 1. The talk, called “Implantable medical devices: hacking humans,” would have showed off security holes in today’s pacemakers, specifically looking at the way they operate and communicate. Jack had been researching this topic since 2012 when an episode of Homeland showed a man’s pacemaker killing a man with a shock to his heart. In his description of the talk posted to the Black Hat website, Jack did not name any manufacturers.

Black Hat announced earlier today that it would not fill in the hour time slot on Thursday that was Jack’s presentation. Instead it will remain empty as a tribute to his work.

Jack had presented about similar attacks in past years. Working with McAfee, he was able to discover a fatal issue in insulin pumps created by Medtronics. He was also known for a hack that sent money flying out of an ATM on Black Hat’s stage while the machine displayed, “Jackpot” on its screen.

A search for his name on Twitter turns up many tweets from people in the security industry paying respect to the late hacker. His company, IOActive, summed it up saying, “Lost but never forgotten our beloved pirate, Barnaby Jack has passed. He was a master hacker and dear friend. Here’s to you Barnes!”