Brazilian authorities have charged a man for allegedly selling access to a 100,000-PC botnet of zombie computers.
The authorities have charged Abreu Neto, 35, for conspiring to cause damage to computers around the world.
It is reported that Neto controlled a botnet of 100,000 remote compromised computers, and leased access to third parties for 25,000 euros (£20,500).
These zombie PCs could then be used to send spam, launch distributed denial-of-service attacks or commit identity theft.
Neto now faces up to five years in prison and a fine of more than $250,000 (£125,000).
"The authorities should be congratulated for their efforts in investigating this case and prosecuting the guilty parties," said Graham Cluley, senior technology consultant at web security software firm Sophos.
"But what about the 100,000 infected computers that were unwillingly turned into foot soldiers for this criminal scheme?" asked Cluley.
"While catching the bad guys is the first step, it is essential that these innocent victims also clean up their PCs.
"Without this, it is likely they will just be playing a waiting game until another hacker exploits their lack of security and recruits them to another zombie network," he said.
Dutch authorities apprehended Neto on 29 July, following assistance from the FBI's New Orleans field office and the Cyber Section of the Brazilian Federal Police.
Neto allegedly worked with a 19-year-old man in the Netherlands to run the zombie network and lease infected computers.