Who broke the window?

Either is acceptable.

Thanks!

Tang
Why do you ask this ?

Is it confusing because it’s a question?

If so, rephrase it into a statement:
Fred broke = simple past tense of break

Fred has broken = verb tense that shows past and continuous.

You seem to have a good grasp of English, yet you ask these basic questions.

There are grammatical features that are found in some languages, but not in others. Being multilingual exposes these differences. I would think that tanguatlay's question is semantical.

You are right!