Public prosecutors failed to substantiate charges at the closed jury trial Tuesday, the suspects' lawyers said.
Ruslan Koblev, a lawyer representing Fail Sadretdinov, a Moscow notary suspected of involvement in the murder, said: "We are astonished. The prosecutors did not provide evidence of Sadretdinov's guilt."
Koblev said prosecutors had also failed to provide evidence to prove that that the murder had been committed by two other ethnic Chechens, Kazbek Dukuzov and Musa Vakhayev.
Klebnikov, 41, the editor of the Russian version of Forbes magazine and a United States national, was gunned down in Moscow on July 9, 2004. He had gained a reputation for investigating murky post-Soviet business dealings and corruption. Investigators said Dukuzov and Vakhayev killed him on the orders of Chechen businessman Khozh-Akhmed Nukhayev, who wanted revenge for a critical book, Conversations with a Barbarian, which featured him as the central figure.
Three other suspects are on the wanted list.
The lawyers earlier asked to summon some 25 witnesses for questioning. Koblev said prosecutors had objected to the questioning, although those people's testimony had been included in the case files.
The defense team is expected to start presenting its case Wednesday.