No arrest warrants have been issued against the three so far, with a decision on whether their detainment should be converted to arrest expected when an examining magistrate has taken their testimony. Meanwhile, police will conduct a search of their homes to seek additional evidence.
Earlier on Friday, police had sent a hefty file of evidence gathered over a year-long investigation into the fire, which seems to point to anti-establishment activists. This includes video footage from surveillance cameras along Stadiou Avenue where the bank was set on fire and also from an attack on the nearby bookshop Ianos.
The cameras show a group of people that broke away from a block of anti-establishment protestors at Ianos and then split into two parties.
It also includes eye-witness accounts that confirm the same conclusions about who was involved in the attack.
The public prosecutor has returned the evidence file at the request of police, however, extending the period of the investigation and agreeing to the detention of the three brought in for questioning. Two of these are suspected of involvement in attacking the bank and a third in the attack on Ianos.