Abdulgadir Masharipov is accused of firing into a New Year's Eve crowd, taking 39 lives and injuring over 70 revellers.
Turkish prosecutors are seeking 40 life sentences for the main suspect in the Istanbul New Year's Eve attack that killed dozens of people.
Anadolu Agency reported, quoting a judicial source, that an indictment of the main suspect, Abdulgadir Masharipov, is ready.
According to the indictment, the Istanbul Chief Public Prosecutors's Office is seeking 40 "aggravated" life sentences for Masharipov, who is accused of opening fire in the crowded Reina nightclub in the Ortakoy neighbourhood in the early hours of January 1, taking 39 lives and injuring over 70.
Masharipov, who is of Uzbek descent, is charged with being a member of an armed terrorist group, deliberate killing, attempting to topple the constitutional order, and the possession of heavy weapons.
The indictment also calls for 15 years in prison for being a member of an armed terrorist group and up to 2,370 years for attempted multiple murders.
The indictment has been sent to the 27th Heavy Penal Court in Istanbul.
The 90-page indictment lists 39 people as the "victims" and 122 people, including 60 foreigners, as "aggrieved."
Fifty-seven suspects are mentioned in the indictment, with 51 of them jailed pending trial.