Minister of Internal Affairs Baurzhan Mukhamedzhanov of Kazakhstan
Mukhamedzhanov said that the organizer and five accomplices had been established and detained.
Mr Mukhamedzhanov said the senate official arrested last week had confessed to ordering the killing of Mr Sarsenbaiuly out of personal enmity.
Mukhamedzhanov said the Interior Ministry had reached an agreement with the US.
Mukhamedzhanov said the investigation team was working on a number of possible motives but did not name them.
Baurzhan Mukhamedzhanov remains as interior minister.
The number of the registered drug addicted persons declined last year, Baurzhan Mukhamedzhanov said at a press briefing.
number of possible motives but did not name them.
Mukhamedzhanov said the motive for the killing was a "long-lasting personal enmity" between the two men.
Interior Minister Baurzhan Mukhamedzhanov said the official had confessed to ordering the killing of Altynbek Sarsenbaiuly two weeks ago.
All seven accused are in custody, and Mukhamedzhanov said all had confessed.