Former President Leonid Kuchma was expected to return to Ukraine on Saturday following the apparent suicide of a former interior minister who was to have been questioned in a killing Kuchma's opponents claimed is linked to both men.
A news agency report from the Czech Republic, where Kuchma has been vacationing, said he has left on a chartered plane headed for Ukraine.
Former Interior Minister Yuriy Kravchenko, found dead Friday, had been implicated in organizing the 2000 killing of journalist Heorhiy Gongadze, who wrote about top-level corruption under Kuchma.
Kravchenko shot himself in the head in his house outside Kiev hours before he was due for questioning about the journalist's murder, said Oleksandr Turchinov, head of Ukraine's State Security Service.
Interior Minister Yuriy Lutsenko said Kravchenko left a note saying he had "become a victim of the intrigues of (ex-)President Leonid Kuchma and his entourage."
Lutsenko cited Kravchenko's note as saying: "I am guilty of nothing. Forgive me ... I am leaving you with a clean conscience."
Gongadze was found decapitated in a forest outside the capital in 2000, which sparked months of protests against Kuchma.
Before Kuchma's reported departure from the Czech Republic, his spokeswoman Olena Hromnytska said he planned to return Saturday from the Czech spa town of Karlovy Vary.
Kuchma said he was prepared to talk to prosecutors, Czech and Ukrainian television reported.
President Viktor Yushchenko said authorities were doing everything possible to solve Gongadze's killing. "We have employed all resources, an army (of people), everything," he said in a speech Saturday at a meeting of his Our Ukraine's party.
State security chief Turchinov told the private 1+1 TV channel that "the testimony of the former president ... appears extremely important for the resolution of the case."
He added that Kravchenko's note "adds pretty much to the investigation."
"This note touches on concrete people who are also suspected in the (Gongadze) case, and gives the investigation the possibility to foresee the further direction of the probe," Turchinov told the station.
He said Kravchenko had shot himself twice at his summer residence in Kiev's elite Koncha Zaspa suburb.
Kravchenko's first shot inflicted only a superficial wound in his neck, but "he was a strong man and he managed to shoot himself again through the right temple," Turchinov said.
Ukrainian television network Inter said Kuchma told reporters he did not believe Kravchenko had ordered Gongadze's killing. He was quoted as saying the former interior minister was under "crazy pressure," partly from the media.
The allegations against Kuchma were based on recordings that a former presidential bodyguard, Mykola Melnichenko, said were made secretly in the president's office.
In the tapes, Kuchma was overheard complaining repeatedly about Gongadze's reporting and ordering Kravchenko to "drive him out, throw (him) out, give him to the Chechens."
Melnichenko said Friday that "Kravchenko's death only plays into Kuchma's hands."
"Fewer and fewer witnesses remain," Melnichenko said by telephone from London. Kuchma has disputed the tapes' authenticity.
The journalist's widow, Myroslava Gongadze, suggested Kravchenko's death was part of a cover-up attempt, saying there were "too many people from the old regime who would try to conceal the true course of events."
"Kravchenko was a key link in the chain of the crime," she said by telephone from the United States, where she now lives.
Yushchenko has made solving Gongadze's death a top priority for his government.
On Wednesday, Prosecutor General Svyatoslav Piskun said investigators had identified all four suspects in Gongadze's killing including two who are in custody and knew who was the mastermind. He refused to reveal the person's identity.
A drone video shows a Russian flag flying over the outermost house in the west of the city.