Hello. Could you tell me the difference between 'report' and 'report on'?

For example, when we call the police (I hope that we don't encounter such an event in our life) because we saw someone stealing valuables from a car on the street, we can probably say "Can I report a crime?" to the police officer. How about "Can I report on a crime?"

"Report a crime" seems to me to be a brief report, either written or oral, and "report on a crime" seems to be a relatively long, well-prepared report, either written or oral, that is given formally at court or in a white paper, for example. But I am not sure.

Generally speaking, I agree with you. However, I'd explain it by offering these simple examples.

He reported a crime. He said 'This crime happened'.

He reported on a crime. He said 'Here is some information about the crime'.

eg On the TV news, they say 'Tomorrow we will report on Obama's visit to Mexico'.

Best wishes, Clive
I agree with Clive and I would add:

He reported a crime. He called emergency services.

He reported on a crime. He worked for a newspaper and reported on a crime for the morning paper. Or, he was a policeman reporting on a crime to his chief. Or...
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Hello Clive,

Thank you for the answer. Your examples are very clear and helpful!

Best regards, Nana
 cwtch's reply was promoted to an answer.
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Hi cwtch,

Thank you for your comment.

Your examples are also easy to understand and helpful for me.

This question came to mind while I was reading an English novel, and I think I could improve my English skills by your answers.

Thanks a lot!