Savisaar is suspected of accepting properties and favors as bribes in 2014 and 2015 with a total value of hundreds of thousands of euros on behalf of himself and his party.

ISS, and the State Prosecutor's Office, which leads the investigation, confirmed that six more people have been named suspects in the case for giving and arranging bribes. All suspects are citizens of Estonia. State Prosecutor Lavly Perling confirmed that they include businessmen Aivar Tuulberg, Alexander Kofkin, Vello Kunman and Hillar Teder, Tallinn City Council Chairman Kalev Kallo, and former politician Vello Reiljan. The latter has been convicted of taking bribes before. Perling agreed to disclose the names to avoid false speculations.

Tuulberg is one of the largest shareholders in construction company Rand & Tuulberg, which among other projects was responsible for the reconstruction of Ülemiste junction in Tallinn and Kultuurikatel, a creative hub in a former power plant near Linnahall. The company also built municipal housing in Raadiku and Meeliku street in Tallinn.

Perling also disclosed that criminal investigation was launched on July 17, 2014 and involves four episodes of bribery. She added that the Prosecutor's Office and ISS have made no arrest as they deem it unnecessary at this stage. The seven people remain suspects.

The Center Party, which was set up by Savisaar in 1991 and is still headed by him, said the arrest is politically motivated. "The timing of the case suggests it's used to muffle the massive Port of Tallinn corruption scandal related to coalition parties," Center Party's press secretary Taavi Pukk said.

Savisaar has been under investigation before, all related to either suspicious financial support for him and the Center Party or unlawful use of Tallinn City Government funds.

In 2010, ISS revealed that Russian Railways President Vladimir Yakunin promised Tallinn's mayor 1.5 million euros to support his political party in Estonia's parliamentary elections in following March.

In 2013, Estonian Prosecutor's Office confirmed that an investigation connected to Savisaar was being carried out under the section of the penal code dealing with money laundering. However, nothing came out of it.

End to a long political career?

Although scandals have repeatedly shadowed Edgar Savisaar before, he has been the longest serving active politician in free and independent Estonia and so far always survived all the controversies.

In 1988, Savisaar co-established the Popular Front (Rahvarinne) which became the first political mass organization in Soviet Union outside Communist Party after 1920. Initially formed to "support perestroika", Popular Front started to develop ideas of Estonian national independence and created so called Singing Revolution phenomenon.

From 1990-1991, he was Estonia's Prime Minister, helping the country to regain independence from the Soviet Union. Savisaar has since become one of the longest serving politicians in Estonia, holding also Minister of Interior and Minister of Economic Affairs and Communications positions. He first became Mayor of Tallinn in 2001, holding this position until 2004 and assuming the post again in 2007.

In the last parliament election on March 1, he was elected to Parliament with a record number of 25,000 votes, although he later resigned as an MP.