The Imam of Jarah wa Tadeel, Imam Ibn Ma'yeen was asked about a man if he's (Thiqa) trustworthy or not?
So Imam Ibn Ma'yeen رحمہ اللہ replied:
كيف يكون من قتل الحسين ثقه
How can be a person (Thiqa) trustworthy when he's a murderer of Hussain عليه السلام?