Golden Dawn deputy Christos Pappas arrested in Greece
A sixth politician from Greece's far-right Golden Dawn party has been arrested after handing himself in to police in Athens.
Deputy party leader Christos Pappas had been sought alongside five other MPs who were held a day earlier.
In all 22 people have been held amid anger over the murder on 18 September of anti-racist musician, Pavlos Fyssas.
A man held for the stabbing told police he was a Golden Dawn supporter, though the party strongly denies any link.
It is alleged he spoke to Golden Dawn MPs after the attack.
Earlier on Sunday, Nikolaos Michaloliakos, Golden Dawn's leader, was charged with belonging to a criminal organisation.
Police earlier said they found three pistols, ammunition and thousands of euros in cash at Mr Michaloliakos's home.
Other charges against some of those held include assault and money laundering.
The latest arrest came as details emerged of the careful planning behind Greece's unprecendented clampdown on neo-Nazis.
According to Greek media reports, several police officers thought to have had links to Golden Dawn were suspended ahead of the operation to prevent them potentially tipping off the targets.
Greek police also arrested one of their own colleagues who was reportedly working as a bodyguard for the party, during a raid on its offices in the western town of Agrinio on Tuesday.
'Shame on them'
The MPs arrested on Saturday were party spokesman Ilias Kasidiaris, Ilias Panayiotaros, Nikos Michos and Ioannis Lagos. It is the first time since 1974 that a party leader and MPs have been arrested.
Justice ministry officials will now have to decide whether to keep the suspects in custody until any trial, BBC Athens correspondent Mark Lowen reports.
Mr Panayiotaros told reporters before giving himself up on Saturday: "Shame on them, the people will lift Golden Dawn higher."
Golden Dawn issued a rallying call via a text message, saying: "We call upon everyone to support our moral and just struggle against the corrupt system!"
Its call for members to gather outside the police headquarters in Athens was answered by some 200 supporters who chanted slogans and waved Greek flags.
Resignations and suspensions
The murder of Mr Fyssas, 34 - whose stage name was Killah P - had sparked protests in Athens and across Greece.
George Roupakias, 45, who said he was a supporter of Golden Dawn, was arrested. He was charged with voluntary manslaughter and illegal possession of a weapon.
The government then launched a crackdown, including raids on Golden Dawn premises.
The government also began an inquiry into the activities of Golden Dawn, which won nearly 7% of the vote in 2012 elections.
Prime Minister Antonis Samaras has vowed not to let the party "undermine" democracy, and government officials say it must now be treated as a "criminal organisation".
Golden Dawn has accused the government of carrying out a witch-hunt over the killing of Mr Fyssas.
On Friday, Golden Dawn threatened to pull its 18 MPs out of the 300-strong Hellenic Parliament.
Mr Samaras's coalition, which has 155 seats, would then face by-elections.
Our correspondent says if Golden Dawn does pull out its MPs it could be the beginning of the end of any political representation for the party in the future.
In recent months, Golden Dawn has been accused of perpetrating attacks on migrants and political opponents - including an attack on Communist Party members earlier this month which is said to have left nine people in hospital.
Golden Dawn officially denies being a neo-Nazi movement, though its badge resembles a swastika, some senior members have praised Adolf Hitler, and its members wear black T-shirts and combat trousers at anti-immigrant demonstrations.