Sarsenbaev was found shot dead on 13 February, along with his bodyguard and driver.
His funeral in the Kazakhstan's commercial capital, Almaty, drew impassioned speeches by opposition activists, RFE/RL's Kazakh Service reported, who reiterated their accusations that the Kazakh authorities orchestrated his killing.
Those allegations are dismissed by Information Minister Yermukhamet Yertysbaev.
"Politics has nothing to do with the case," he said today. "I want to state once again that all measures are being taken to find the criminals and we should wait for official information from the Interior Ministry."
Deputy Prosecutor-General Ilyas Baktybaev said the deputy interior minister is "personally involved" in overseeing the investigation.
Kazakhstan's parliament today held a special session to discuss Sarsenbaev's slaying.
Sarsenbaev, a former ambassador to Russia, twice served as head of the Information Ministry before joining the opposition. He was the second prominent opposition figure to be found shot dead in recent months.
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