Is it true that Shincheonji members joined the Democratic Party?

There is no evidence that they joined systematically under anyone's orders,
and there is only testimony, right?
The truthfulness of the testimony hasn't been verified, but the testimonies are supposedly linked to each other.
Then they should just start by investigating the people who gave the testimony and launch an inquiry.
Why aren't they doing it?
Is the Democratic Party the kind of party that won't even investigate if Shincheonji is present? lol