Ukrainian businessman Vitaliy Haiduk, a witness in the criminal case on the murder of MP Yevhen Scherban, has said he can neither confirmed nor deny the involvement of former Prime Minister of Ukraine Yulia Tymoshenko in the murder.

"I have no direct evidence that Yulia Tymoshenko ordered the murder of Scherban. But I have no evidence to the contrary, either. I do not know this," he announced during the questioning in Scherban case in court on Tuesday.

The witness said this in reply to the questions by the ex-premier's defense counsel. At the same time, he protested against the provocative questions by Tymoshenko's defense team about whether he has evidence against the former prime minister.

"You have asked me a provocative question. I have either to wrongly accuse or to wrongly justify," Haiduk said addressing Tymoshenko's defense.

Haiduk said that he was "not a party to the relationship between Tymoshenko and Scherban."

According to the witness, the relations between the Industrial Union of Donbas (ISD) and the United Energy Systems of Ukraine (EESU) were exclusively businesslike.

"These relations didn't go beyond the scope of business process. And there can never be perfect relationship in business," Haiduk said. However, he stressed that "at that time it was the best possible compromise," and all the issues were resolved at the negotiating table.

Haiduk said that the gas supply agreement between the ISD and the UESU was signed on December 30, 1995. Since November 1995, Oleksandr Momot represented the ISD in the talks, while Tymoshenko represented the UESU.

An Interfax-Ukraine correspondent said that Tymoshenko was not brought to the court for Haiduk's questioning.

As reported, Yevhen Scherban, a member of the Liberal Party's executive committee and a Verkhovna Rada deputy, was shot dead at the Donetsk airport on his arrival from Moscow on November 3, 1996. The gunmen fled the scene by car. Scherban, his wife and a mechanic died on the spot from gunshot wounds. The plane's flight engineer died later in the hospital. Law enforcement officers ruled out there being political motives behind the case.

In April 2003, the Court of Appeals of Luhansk region sentenced Vadym Bolotskykh to life imprisonment for Scherban's murder.

Scherban's son, Ruslan Scherban, a member of Donetsk Regional Council, said at a press conference on April 4, 2012 that he had passed to the Prosecutor General's Office documents indicating Tymoshenko's and former Ukrainian Prime Minister Pavlo Lazarenko's possible involvement in his father's murder.

Tymoshenko and Lazarenko have categorically denied being involved in the murder.

On January 18, 2013, Prosecutor General Viktor Pshonka said at a briefing that the Prosecutor General's Office had finished its investigation into the criminal case on the murder of MP Scherban and that Tymoshenko had been notified of being suspected of having organized the crime, along with Lazarenko. The article of the Criminal Code under which the notification was handed envisages life imprisonment. According to Pshonka, Tymoshenko and Lazarenko paid $2.8 million for Scherban to be killed.

In February-March 2013, three witnesses for the prosecution and one witness for the defense were interrogated in court as part of the pre-trial investigation into the Scherban murder case.

Tymoshenko did not attend either of the court hearings.

On October 11, 2011, Pechersky District Court in Kyiv sentenced Tymoshenko to seven years in prison for overstepping her authority when signing 2009 gas contracts with Russia. She has served her sentence in Kachanivska Penal Colony in Kharkiv since late December 2011. The ex-premier is currently undergoing treatment at a Kharkiv-based hospital.