Subpoena the records and be sure that the subpoena says that if the records have been destroyed, you'll do 15 to life.
Hmmmm 'subpoena' them under what authority?
A criminal investigation. Voter rolls are not private records.
What 'criminal investigation'?
Voter rolls are under the authority of States.
And I know Conservatives hate the concept of state's rights, but States, under their own constitution's- control their own voter's records.
So far all you have is a Presidential commission- with no authority over anyone- politely asking for information so they can go on a wild goose chase trying to support President Snowflake's lie about illegal votes.
And California has chosen to tell them to go pound sand.