Moscow (AFP) - A judge hearing the murder trial of Kremlin critic Boris Nemtsov on Tuesday refused a request to call Chechen strongman Ramzan Kadyrov for questioning.
Nemtsov, a former deputy prime minister who strongly criticised President Vladimir Putin's rule was gunned down near the Kremlin in February last year.
Five Chechens are on trial for the murder at a Moscow military court.
But the judge rejected a plea from lawyer Vadim Prokhorov, representing the murdered opposition politician's family, to summon the pro-Kremlin Chechen leader.
Prokhorov argued that Kadyrov, who was on bad terms with Nemtsov and had criticised him, could have information on the murder.
"Nemtsov's conflicts with various political figures are not a basis to summon them to court," the TASS state news agency quoted judge Yury Zhitnikov as saying.
Nemtsov's family and allies say the authorities have failed to bring the masterminds to justice and point the finger of blame at Kadyrov as well as at the Kremlin itself.
Nemtsov's daughter had asked investigators to question Kadyrov as a witness but this was refused.
Kadyrov in turn said he was "willing to give testimony, with pleasure" at the trial in an interview with TASS last week.
Three of those on trial served in a Chechen unit of interior ministry troops known as Sever, or "North", which supports Kadyrov and has taken part in operations against insurgents.
In an important move, the judge on Tuesday agreed to summon Sever's commander Alibek Delimkhanov for questioning along with his deputy.
Delimkhanov was decorated as a Hero of Russia in 2009 for fighting insurgents in the North Caucasus. He is reportedly Kadyrov's cousin.
The judge rejected a plea to question Alibek's brother Adam Delimkhanov, an MP for Putin's ruling party.
The defendant whom the prosecutors say fired the fatal shots -- Zaur Dadayev -- is a former deputy commander of Sever. Kadyrov after his arrest praised him as "a real patriot of Russia."
Another man who was named as an organiser but has fled Russia, Ruslan Mukhudinov, also reportedly served in the same unit, as did a third suspect, Beslan Shavanov, who blew himself up as he was detained.