"Unfortunately, we've got no answer," said the ambassador.
Kudryavtsev noted that he has not yet got an official notification of the seizure of the Russian nationals. "I don't know what the charges against them are. I've not been officially shown the documents and charges," the ambassador said.
He said that lawyers of the Russian Foreign Ministry are studying details of the Qatar legislation and international agreements to see how the case can be tried.
Earlier, the ambassador said that the Russian embassy had asked the authorities of Qatar for daily visits to the detained Russians. "I hope the Qatar authorities will consider the matter promptly and positively," Kudryavtsev said.
"The head of the embassy's consular division has met with the detainees. They do not lament over the conditions of detainment", ambassador Kudryavtsev said.
On the night from February 18 to 19, the local secret services detained in Doha the three Russian nationals found on a business trip to the Russian embassy. One of them has been released and is now in the embassy.
The Russians are accused of being involved in attempt on Yandarbiev's life.
Russian acting foreign minister Igor Ivanov has called "provocation" these allegations. In the statement circulated at night Ivanov demanded from the authorities of Qatar immediate release of the unlawfully detained Russians.
"The arrest was made with the use of arms and rude force," Igor Ivanov's statement reads.
"The Russian state is taking vigorous steps to protect its citizens. Within the framework of these steps a special representative of the Russian foreign minister has been sent to Doha for negotiations with the local authorities," Igor Ivanov said.
"The official Russian representatives have already said that our country has nothing to do with the incident. The attempts by the authorities of Qatar to shift the responsibility for the attempt at Yandarbiev's life on the seized Russian nationals are groundless: they are in no way connected with the incident. The Qatar authorities' insinuations can only been seen as provocation", the statement reads on.
Igor Ivanov also noted that Yandarbiev was listed by the United Nations as one of the most dangerous international terrorists. "In line with the UN antiterrorist resolutions, every state is obliged to indict or extradite terrorists to the countries where they have committed crimes," Igor Ivanov recalled.
His statement was handed over to Qatar ambassador in Moscow Saad al-Kubeisi, who has been summoned to the Russian Foreign Ministry.
The Qatar prosecutor's office has already charged two Russians suspected of arranging the murder of Zelimkhan Yandarbiev. A spokesman for the Interior Ministry said that the two suspects, whose names are not disclosed, were seized on February 19 and charged on February 25.
Earlier, the newspaper Al-Shark al-Awsat wrote that the two suspects were detained in the airport of Dubai (the United Arab Emirates) and passed to the authorities of Qatar. From Igor Ivanov's statement follows that the detainment took place in Qatar.
Yandarbiev's car was blasted on February 13 in central Doha. His son-in-law and driver died on site and Yandarbiev proper died of wounds later. His son Daud is in hospital.
The Qatar newspaper Al-Shark with reference to Lieutenant-General Mubarak Hasan al-Nasr, general secretary of the General Security Service, writes that Yandarbiev had no bodyguards and officers from the General Security Service only protected his residence, where he had lived for the last three years.