What is the best way in a timely manner to obtain this vehicle?

My dad was giving me a car before he passed. His relative came to TX, drove him to NJ (before he left, he had signed the title to me (the actual document). He went from the car to life support when he arrived at his mothers driveway, and died a few days later. After I went up there to make life decisions for him, I came back home, explained everything to the DMV, and had the title put in my name.

My grandmother is refusing to release the car, and has it in a gate at her house in NJ. She claims she HEARD there’s a will that is being probated in 30 days (it’s been nearly 60 days since his death, so I doubt that). My dad was stubborn, and never signed anything while he was living. He did not have any real property or assets to make a will with, (He lived in a apartment with only a couch). The only thing he had to his name was this car (which he recently purchased last year) and a iphone/ipad.

I've tried to contact the police in both states to file a stolen vehicle report, but they claim since its my grandmother (family), and since I put the title in my name after he died, its a civil matter. So I think this heard there's a will is a bluff to scare law enforcement/delay things.

He was never married, I am his only child (heir), and his last known residence was in TX. It shows in the death certificate, and the car was purchased in TX. The value of the car is in excess of $10,000.

I also had a attorney send her a certified demand letter, which she has not responded to.

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