By Paul Anderson
Kazakhstan's opposition has demanded the resignation of the head of the upper house of parliament, following the murder of an opposition politician.
Sarsenbaiulu is the second opposition leader to die recently
It comes after an aide to the speaker was reported to have been arrested in connection with the investigation.
The opposition media have continued to pressurise Kazakhstan's political establishment after the killing of Altynbek Sarsenbaiulu 10 days ago.
Mr Sarsenbaiulu was shot dead along with his driver and bodyguard.
Bound and shot
There has been no let-up in the pressure Kazakhstan's opposition politicians and newspapers are piling on figures in and associated with the government over Mr Sarsenbaiulu's killing.
This came as the resignation of the country's security chief, Nartbay Dutbayev, was confirmed on Wednesday.
Five of his officers have been arrested.
Mr Sarsenbaiulu, his driver and his bodyguard were found outside Almaty with their hands tied. They were shot in the head.
Leaders of one opposition bloc, For A Just Kazakhstan, reported that the head of the Senate's administration, Erzhan Utembayev, had also been arrested.
Several newspapers round on other high officials they believe may be linked to the case.
Thousands of ordinary people turned out to Mr Sarsenbaiulu's recent funeral, revealing the public outrage at the second death of an opposition leader in the past three months.
Last November, the prominent politician, Zamanbek Nurkadilov, was found dead with gunshot wounds.
The authorities ruled his death a suicide.
President Nursultan Nazarbayev, who has ruled Kazakhstan for 16 years, said the latest killing was a challenge to the whole of society.
He promised to bring those responsible to justice and has enlisted the help of the American Federal Bureau of Investigations (FBI).