How to access 13D/G Filings

Hello,

I am currently programming a tool for a client that is supposed to deliver the 13D/G Filings of a specific activist investor e.g. "tang-capital-partners-lp". Currently I cannot find any API Request that allows this kind of request. What is the solution to get the data that is accordingly presented on the https://fintel.io/i13d/tang-capital-partners-lp from an API Request.

Best Hannes