The parcel bomb went off inside a police station

The bomb exploded at a police station on Friday, injuring three officers.

Investigators said they believed the man was part of a professional criminal network and have ruled out any terrorist connection.

They say the bomb was more powerful and technically more sophisticated than a recent series of parcel bombs sent to Italian and European politicians.

Those attacks were blamed on anarchists.

Fingers amputated

Three policemen were injured when the bomb exploded as the officers were examining it.

One of the wounded policemen had to have two fingers amputated and parts of two others removed, reports news agency AFP.

The parcel had been sent to a woman, who became suspicious when she found a video cassette inside and alerted police, said AFP.

LETTER BOMB TARGETS 28 December: Romano Prodi (European Commission president) 29 December: Europol (EU criminal intelligence service); Jean-Claude Trichet (European Central Bank chief) 30 December: Eurojust (EU body working for judicial co-operation) 5 January: MEP Hans-Gert Poettering; MEP Gary Titley; MEP Jose Ignacio Salafranca

Police dismissed any suspicions of a terrorist motivation after interviewing the woman.

Italian authorities have blamed Italian anarchist groups for previous parcel bombings.

In December and January, a number of letter bombs posted in Bologna, Italy, were sent to European Union officials, including former Italian Prime Minister Romano Prodi, who is president of the European Commission.