Can the police issues a search warrant that was sign by a person who is blood related

First of all a judge issues a warrant, not the police. Second, a blood relative can give the evidence necessary to establish probable cause.

Police do not issue search warrants, they request them and a judge has the final decision. This is your 2nd similar question about this warrant. You should get on the phone and call a few local criminal attorneys to discuss. Best of luck.

Is your niece a judge? Judges sign search warrants. Sounds like you need to retain a criminal defense attorney.

I would need to know more about the circumstances of the warrant. I am assuming the police searched your residence. Was the judge who signed the warrant your niece, or was your niece the police officer? Normally, a search warrant is signed by a police officer and a judge or magistrate.