interview update

Hello, I just completed the interview (third run and the final one). Do I need to send the “thank you letter” to all attendances again?

PS. It is helpful after provided my advisors name (who is a well-known prof. in the area the hiring company is working on) and my previous boss/ directors name (who is a well-known leader in the area I am applying for). The hiring director called my advisor immediately after I mentioned his name. Seems they know each other very well.

Thanks for all your suggestions!