identify (someone or something) by (something)
To use some specific characteristic to recognize someone or something. You'll be able to identify me by my red hair and purple dress. I can identify a plagiarized report by the writing, you know—and this is definitely a plagiarized report.
identify someone or something by something
to recognize someone or something because of something. Can you identify your baggage by any special marks? You can identify me by the red carnation in my lapel.