MOSCOW, July 7 (RIA Novosti) - The Russian Prosecutor General's Office said Tuesday it had agreed on closer cooperation with the U.S. Justice Department on a probe into the 2004 murder of Forbes Russia editor Paul Klebnikov.

Russian Prosecutor General Yury Chaika met with Klebnikov's widow and brother two days prior to the fifth anniversary of the journalist's death and informed them of the course of investigation.

The meeting was also attended by Russia's chief investigator Alexander Bastrykin, the Klebnikov family's lawyer, as well as a U.S. Justice Department official from the U.S. embassy.

A memorial service for Klebnikov took place on Tuesday in Russian and English in central Moscow's Christ the Savior Cathedral.

A U.S. citizen of Russian descent, Klebnikov, 41, was the editor of Forbes Russia from its launch in April 2004. He gained an international reputation for investigating murky business deals and corruption in the post-Soviet era, and was killed leaving his office in central Moscow in July 2004.

A top Russian investigator said on Friday the investigation into the murder, which was suspended earlier in the year, has been resumed.

Two Chechen men were charged with killing Klebnikov, allegedly on orders from a Chechen warlord, but they were acquitted and freed in 2006. The Supreme Court ordered their retrial but the trial was suspended after one of the defendants went missing.