Why it is have?

[naveen]

correct sentence:
Did you notice any particular characteristics about the thief — did he have long hair?

Correct entry: did he have
The error was: (d) was he wearing

You have found the error but your entry is incorrect.
your sentence:
Did you notice any particular characteristics about the thief — did he has long hair?

[Yankee]

Hi Naveen

To make a question in the simple past tense you need to use did + infinitive. (did he have)

"Did he has" is never correct.

Amy