Greek justice on Friday began interviewing dozens of suspects over the fatal stabbing of a fan near Athens ahead of a Champions League game this week.
A 29-year-old man, Michalis Katsouris, died after a brawl between hardline supporters of AEK Athens and Croatian club Dinamo Zagreb on Monday.
In light of the tragedy Tuesday's third round qualifier between the two sides was subsequently postponed until August 19 by UEFA.
Police made around 100 arrests - the majority said to be linked to Dinamo's 'Bad Blue Boys' ultras, according to a judicial source.
Three judges are conducting the interviews which are expected to be completed on Sunday night, local media reported.
Greek Prime Minister Kyriakos Mitsotakis and UEFA president Aleksander Ceferin "spoke on the matter by telephone" on Friday, an official statement announced.
The pair will meet in Athens next Wednesday to discuss "what is happening in Greek and European football", the statement added.
Ceferin, Mitsotakis and other government ministers will then hold a meeting with the owners of Greece's four big clubs - Olympiakos, Panathinaikos, AEK and PAOK.
On Tuesday the Greek minister for citizen protection suspended seven police officers for not ensuring adequate security measures to prevent the brawl.
The death of Katsouris has shocked a nation grown accustomed to violence erupting at football matches.
This week's tragedy follows the fatal stabbing last year of teenager Alkis Kampanos in the northern city of Thessaloniki during a fight between supporters of the city's rival clubs Aris Thessaloniki and PAOK.
Following that death the government increased the maximum sentence for fan violence from six months to five years.
Last month, seven defendants were found guilty of Kampanos's murder and handed life terms with five others jailed for complicity.
Police meanwhile have beefed up border security in the wake of this week's killing.
On Thursday seven Romanian fans were arrested on the border between Greece and Bulgaria in possession of two knives.
They were handed one year suspended prison terms on Friday and each fined 1,000 euros ($1,095), a judicial source reported.
According to police they were on their way to Thursday's Champions League qualifier between Olympiakos and Belgian side Genk.
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