An investigating magistrate had issued a warrant for the suspect’s arrest in connection with the letter bombs sent to “various recipients in European Union countries” in March and another device targeting Mr. Papademos in May, according to the statement.

The suspect is believed to be linked to a Greek extremist anarchist group called Conspiracy of the Cells of Fire which claimed responsibility for sending the parcel to Mr. Schaeuble earlier this year.

Image Lucas Papademos in Athens in 2011, the year he became prime minister. Credit... Yannis Behrakis/Reuters

The group first made its mark with a barrage of parcel bombs sent to European leaders in 2010, when, teetering on the edge of bankruptcy, Greece agreed to its first international bailout. Several convicted members of the group are serving long prison sentences for terrorist activities.

Mr. Papademos, a 70-year-old economist who was prime minister for six months from late 2011 to early 2012 during the height of Greece’s debt crisis, was seriously hurt when a parcel bomb exploded in his hands as he opened it in his car in Athens. No group claimed that attack, but at the time, the police drew parallels with earlier attacks targeting Mr. Schaeuble and the I.M.F. offices in March. In all the cases, the letter bombs contained gunpowder.