poroshenko
© Serhly Dolzhenko/EPA- EFEFormer Ukrainian president Petro Poroshenko (center)
Former Ukrainian President Petro Poroshenko has failed for the second time this week to show up at the State Bureau of Investigations (DBR) for questioning.

The DBR planned to question Poroshenko on May 29 as a witness in two cases -- the alleged illegal transfer of cultural objects across the border and in connection with audio recording of individuals with voices thought to possibly be of Poroshenko and former U.S. Vice President Joe Biden.

Last week, lawmaker Andriy Derkach said the audio records prove "high treason" by Poroshenko.

Poroshenko's lawyers, Ilya Novikov and Ihor Holovan, said on May 28 that their client wouldn't show up at the DBR because the summons for questioning had been made via the DBR's website, which is "illegal" since their client should have been served the subpoena personally.

Poroshenko used the same explanation for ignoring a DBR summons on May 26, where investigators wanted to question him as a witness in a case about "the circumstances of moving across the Ukrainian border, without presenting to customs services, a collection of cultural objects, consisting of 43 paintings by world-famous artists."

Instead of going to the DBR for questioning on May 26, Poroshenko took part in the opening of an arts exhibition in the Kyiv-based Ivan Honchar Museum, at which the paintings mentioned in the case were on display.

Museum officials said on May 29 that DBR officers had impounded the paintings a day earlier.

Poroshenko, who is currently a deputy in parliament, has been questioned as a witness several times in recent months in cases looking into several investigations launched after he failed to win a second term as president.

The DBR said in January that it was looking into 13 possible cases in which Poroshenko or his associates were implicated.

A billionaire confectioner, Poroshenko and his party ran on a pro-European, anti-Russian ticket in July parliamentary elections, winning 25 seats.