ATHENS – A 29-year-old man arrested in connection with the letter bomb sent to former interim Premier Lucas Papademos, who was injured when it exploded in his car, is being looked at by police who want to see if he has links to two terrorist groups.

Authorities are also investigating whether the groups are tied to other similar attempted hits, said Kathimerini. The suspect, who was not initially named, was later identified as Constantinos Giagtzoglou, who was under surveillance for two months before being arrested as police said he was trying to get rid of a cache of guns, explosives and eight fake police ID cards.

Police were said to believe he has close ties to the notorious Conspiracy of the Cells of Fire, some of whose members are in the high-security Korydallos Prison where it was earlier reported they are still directing violent activities outside.

Police are also probing possible links between the suspect and another guerrilla group, Revolutionary Struggle. Police feared that the 29-year-old had been planning another attack, probably on behalf of the Conspiracy of the Cells of Fire, the paper said.

They are also thought to been the ones who sent a similar letter to bomb to German Finance Minister Wolfgang Schaeuble, whose country has put up the bulk of 326 billion euros ($379.32 billion) in three international bailouts for Greece that came with brutal pay cuts, tax hikes, slashed pensions and worker firings.

That package was intercepted before it could go off but another bomb, sent to the offices of the International Monetary Fund in Paris, one of Greece’s lenders, did go off, injuring a secretary.