Dooku died around 32 yrs BBY
One thing that I am actually becoming tired of is the continuing usage of people using the name Dooku.
Count Dooku - Count of Serenno and Respected Jedi Master died around 32 years BBY.
The moment that Dooku left the Jedi order and became Darth Sidious' second last apprentice was the time of his death.
The name Count Dooku, and the usage of that name by anyone in the Republic and or the CIS is just formality.
Count Dooku was nothing more than a public facade. Made to keep up appearances and to sway beings into gullibility.
Assassination is not in his character - Mace Windu (AOTC).
Count Dooku ceased being known by that name and instead became Darth Tyranus. At this point there was no longer any benevolence or justice or righteousness left within him. As the name Lord Tyranus suggests, he was and would have become a Tyrannical oppressor of freedom. He killed Jedi Master Sifo-Dyas (a long time friend and confidant) as his first show of loyalty to the Sith.
To kill a friend and colleague as a test of loyalty shows that "Count Dooku" to all intents and purposes had ceased to exist and had from that time forth become known as Lord Tyranus.
Just as Anakin Skywalker ceased to be known as such and had become Darth Vader.