My car keys have been stolen and the person who took them is now claming she does not have them, what can i do?

ok so here is the story, i been in a relationship with this girl for over 7 years and about a week ago we broke up. She decided to take revenge and planned out this 'talk" that she wanted to have before we really stop talking to eachother. so basically her intentions were to take my car keys while we were having this talk and then she ran out of the vehicle into her house. she claims that she payed half of the car, but such imformation is not true. the car is under a moms friend. and i have proof that i make monthly payments on the car. well anyways, she ran in the house and didnt want to give me the keys. she began to say that she threw the keys into a bush but i knew that was not true. then i see her cousin walking out of the house very suspiciously and she leaves the house with my x girlfvriend. i did not want to call the cops in this sittuation due to the fact that i did not want to be accused of hitting her since she was already begining to make statements that i pulled her hair when obviously i was just trying to take my keys. i ended up staying all night out side the house with a friend, because we were stranded with no keys, until we got a ride home. i then began to feel very impatient and told my x that if she didnt return my keys that i was going to make a police report. she began to get very scared and told me she handed the keys to her cousin. she claims that her cousin put the keys in a locker in her work place, and she cant take the keys out until monday. she began to opologize saying it was a mistake and she wasnt thinking, she was just angry that i broke up with her. so i texted her cousing and i asked her for the keys, she denyed it, and i stated that if she didnt return them that i was going to call the cops and i was going to enjoy watching the police open up her locker and finding my keys. and at that moment she began to get a little worried in my opinion. her x husband is a police officer and she has a kid with him, so her reply to my text was that i threatned her life so that if i called the cops that i was the one going to jail for harrasment. then later, i get texts from her husband mike, the police officer, and he begins to tell me to let it go or im going to get my self thrown in jail by him. he claims that she does not have the keys, but later tells me to wait it out until monday. the police officer is covering up for her and i really feel so powerless. i did read the text messege that i sent her and i guess it could be used against me. his exact words were, 'i know what you told my wife and that was a terrorist threat and i will personally arrest you and book you in if you don't stop what you are doing right now' i replyed "look mike im sorry i will stop but its just that esther stole my keys and gave them to your x wife. what should i do in this sittuation, i really need my car? and the police officer replys 'it is what it is, let it go before you get your self in to trouble, if you are wondering what the charge is it is pc 422 terrorist threats, you are putting my babys mom in danger and i have to look out after her so drop it'

this police officer is obvious;ly not coaperating since thats his babys mom. i dont want to get my self thrown in jail because of this. my car is basically stolen and i cant do nothing about it. all i have is witnesses that she took my keys and evidence saying that her cousin has my keys, well text messeges from the cop and from her cousin, what can i do in a sittuation like this i really need help, i need my car. thank you for reading