sister says I have some of her stuff...threatening police warrant

What is the name of your state? Maryland

My sister left some of her property (clothes, etc...nothing of any great monetary value) in the trunk of my car after we got in an argument. She lives in WV and says I have until Friday to return her things to a family member here in MD....OR....that the sherrif's dept. in the town I live in said she can come down here to file a complaint and they will come to my house with a warrant to search.

Is this correct? Thanks!!

Your sister is funny. Your sister can file a complaint but the police will do nothing. They will tell her it is a civil, not a criminal matter. You can send her a letter, certified, return receipt requested, stating that you are going to charge her storage for her items if SHE does not come and get the stuff. Also state that if the items are not picked up in 30 days, you will sell the items to cover the cost of storage. If by chance you are contacted by the police, tell them she left the stuff with you, do not under any circumstances say anything about taking anything without permission. But I doubt you will even hear from the police.