A man who died in custody this week was arrested during raids in Perth in which police seized about $33 million worth of drugs.
The raids recovered 32kg of methylamphetamine, 1.8kg of cocaine, 300g of MDMA, three guns and more than $850,000 cash.
Detectives investigating a suspected criminal network on Monday raided several properties in City Beach, West Leederville, Gnangara, Applecross, Madeley, Dayton and Ascot.
Assistant Commissioner Michelle Fyfe revealed on Wednesday that a 27-year-old man was arrested in Ascot, became ill and died in hospital. She said he had not been tasered.
Police had revealed the death on Tuesday but did not disclose details of the raids at the time.
Assistant Commissioner Fyfe said Homicide Squad detectives and the Internal Affairs Unit were investigating it as a death in custody.
"Because it is being investigated on behalf of the coroner there is nothing more that I can say," she told reporters.
Police said the drugs had an estimated street value of more than $33 million.
In its sale form, the meth represents 320,000 hits of the drug.
Three other men have been charged with a total of 21 offences including possessing an unlicensed firearm, possessing stolen property and possessing prohibited drugs with intent to sell or supply.
Two of the men, aged 23 and 27, appeared in Perth Magistrates Court on Tuesday and had their cases adjourned until next week.
Another 27-year-old man appeared in the same court and had his case adjourned until December 5.