The Ascot home of a man who died in custody on Tuesday was part of a series of raids across Perth, uncovering more than 30 kilograms of methamphetamine, several firearms and more than $800,000 cash, WA Police say.

Organised Crime Squad detectives have charged three people over the massive haul of drugs.

Police have seized more than 30 kilos of meth in a massive WA drug bust. Three men have been charged. Firearms and $800,000 in cash were also seized. Credit:Phil Hickey

Assistant Police Commissioner Michelle Fyfe spoke to reporters on Wednesday, and confirmed a 27-year-old man who died in custody was believed to be connected to a suspected drug syndicate.

Some steroids were seized at the man's home and she said she did not believe the man had been Tasered or that there had been a physical altercation during his arrest.