Greek magistrates on Tuesday ordered the pre-trial detention of a seventh lawmaker from the neo-Nazi party Golden Dawn, several of whose members are under investigation for criminal activity, a justice source said.

Nikos Kouzilos, a 37-year-old tanker captain from Piraeus, joins party leader Nikos Michaloliakos and other senior Golden Dawn members who are being held for alleged participation in a criminal organization.

Kouzilos was the party’s candidate for mayor of Piraeus in last month’s local elections.

A crackdown against the party was launched last year following the killing of a Greek anti-fascist musician by a Golden Dawn member near Piraeus.

Other cases allegedly involving Golden Dawn members are the murder of a Pakistani migrant, assault against political opponents and illegal possession of firearms and weapons.

Nazi and fascist memorabilia were also found in the home of Golden Dawn’s deputy leader earlier this year.

Formerly on the fringe of Greek politics, the openly xenophobic and anti-Semitic Golden Dawn won entry to Greece’s 300-seat parliament for the first time in elections in June 2012, tapping into widespread anger over immigration and austerity reforms in the debt-ridden country.

Golden Dawn also ran third in European elections last month.

A date for the criminal trials has not been set.