Police in Spain have arrested three men, believed to be members of the notorious hackers' organisation known as Anonymous.

The men were arrested in connection with Anonymous' alleged activity in the country and were the result of Spanish police trawling through millions of lines of chat logs involving the groups supporters.

The arrests were made simultaneously during raids in the cities of Barcelona, Valencia and Almeria and follow arrests in the UK and the US of suspected Anonymous members.

Masterminds

The big break for officers came when they gained an insight into users of the LOIC internet program, which is used to execute denial of service (DDoS) attacks on websites, by bombarding them with data until the servers crash.

Apparently the LOIC platform, which Spanish police called a "cornerstone" of the hacking community, wasn't doing the best job of covering the identity of its users.

Household name

Anonymous became a household name in April when Sony accused the 'group of connected internet citizens' of masterminding the PlayStation Network hack, which compromised the data of 77m users.

The group denied that hack, but Spanish authorities claim to have made one of the arrests at an apartment which housed a server that had been used to attack the PlayStation Store, as well as banks and government websites.

The group has also been a staunch supporter of the whistle-blowing site Wikileaks and is believed to have carried out many attacks on its behalf.