Copenhagen Suborbitals

For a while, Madsen even lived aboard it.

He'd also co-founded an amateur spaceflight company called Copenhagen Suborbitals with a fellow enthusiast named Christine von Bengtson.

Their dream was to build a rocket from scratch and one day launch a person into space.

But in 2014, the two men had a falling out.

They stopped listening to Madsen's story and started looking at the man telling it.

While divers kept searching the water, detectives went to talk to the people around him, and what they found was a man almost nobody had really known.

They started with his coworkers, the volunteers from Copenhagen Suborbitals and from his current outfit, Rocket Madsen Space Laboratory.

These were people who'd signed up because they believed in Madsen and his mission.