MOSCOW, March 5 - The chief of Ukraine's security service said Saturday that the country's former interior minister, Yuri F. Kravchenko, had shot himself twice in the head on Friday, refuting speculation that he had been killed by someone else.

The official announcement and a note found in Mr. Kravchenko's pocket, the security chief added, left little doubt that Mr. Kravchenko had committed suicide.

Oleksandr V. Turchinov, chairman of the Security Service of Ukraine, said in televised remarks that the note left by Mr. Kravchenko could provide significant details for prosecutors investigating the killing of Georgy Gongadze, a prominent journalist whose death in 2000 provoked protests and international criticism of Leonid D. Kuchma, who was then the president.

Mr. Kravchenko, who served as interior minister at the time of Mr. Gongadze's abduction and killing, was found dead Friday at a country cottage outside Kiev.