Cocaine envelope sparked fatal DJ stabbing

A man who fatally stabbed a 41-year-old Perth DJ after they argued over a lost envelope containing cocaine claims he acted in self-defence.

Jaime Rodolfo Fernandez, an event organiser known as "DJ Suave", was found under a running shower in his Tuart Hill home in July 2016, four days after he was stabbed to death.

A man who lived in a unit below Fernandez and heard the constantly running water initially told the strata manager about it, but was told nothing could be done, so he eventually alerted police, the Supreme Court of WA heard on Thursday.

Defence lawyer Jeremy Scudds told the jury Fernandez was a drug dealer and a fight broke out between him and Victor Amaya, 28, when his client went to the unit to deliver event tickets in envelopes.

Mr Scudds said Fernandez became angry because Amaya had lost one of the envelopes, not realising it contained cocaine.

The trial continues.