The charges against him claim that he received kickbacks from Siemens (between 1998 and 2000) from a contract awarded to the German electronics company to digitise the Greek state telecom's systems.
On trial with Mantelis are businessman Georgios Tsougranis, tax office employee Antonia Markou, former Siemens executive Ilias Georgiou and his associate Aristidis Mantas.
So far, Mantelis is the only politician that has been convicted in connection to kickbacks made by Siemens to Greek decision-makers and public officials to secure state contracts.
The Siemens bribery scandal was a corruption and bribery scandal that hit Greece over deals between Siemens AG and Greek government officials during the 2004 Summer Olympic Games in Athens regarding security systems and purchases by OTE in the 1990s (or during PASOK rule). Charges have, as of 27 August 2008, not been brought against any specific individual, as under Greek law charges can be filled against "any responsible person". So far, no wrongdoing has been proved, either by Siemens, by Greek government officials, or anyone else.
It has been claimed that the political outcome of the case may be analogous to that of Italy 15 years ago and most importantly that the bribes may have been up to 100 million Euros.
Some believe that when Costas Karamanlis rose to power, he did not send this case to justice, but they were wrong. The case was immediately sent to justice, and following several years of investigations a Greek prosecutor filled charges on July 1st, 2008 for money laundering and bribery.
Tasos Mantelis who was Minister for Transport and Communications during the PASOK administration in 1998 admitted in May 2010 to a parliamentary investigation committee that the sum of 200,000 German marks was deposited in 1998 in a Swiss bank account from Siemens during his administration, allegedly for funding his election campaign. A further deposit of 250,000 German marks was made into the same bank account in 2000 which Mantelis claims is from an unknown source.
Source in Greek - in.gr