罪魁祸首 (zuì kuí huò shǒu): The main culprit / The principal offender — Meaning & Stroke Order

After investigation, he turned out to be the main culprit of this accident.

Don't you understand yet that procrastination is the main culprit behind your project's failure?

The main culprit of environmental pollution is the exhaust gas emitted by factories.

Stop making excuses; you yourself are the main culprit for being late to this date.