You can definitely know that something is done without knowing who, exactly, did it. “A person formally or informally affiliated or aligned with the Israeli state”, if we have to use the State Dept lingo for terrorists.

I have a right to make personal conclusions based on things I see, read, learn and hear, what's your point?

Whether its biased, wrong, correct - my personal opinion and conclusions are still mine, hence I prefixed it with "my personal conclusion"