Can I hire a lawyer if I haven't received the notice of criminal detention?

Sure! If there is a detention notice, it should be brought to the law firm to let the lawyer know the specific situation in detail, which is helpful to handle the case. If there is no detention notice, you can also go to the law firm to handle the entrustment procedures and pay the lawyer's fee. But before hiring a lawyer, it is best to know as much as possible about the basic situation of the case, such as what the suspect was detained for, when he was detained, and the course of the case, so that the lawyer can serve you better.