Bought SUV and friend titled it in her name temporarily. She now refuses return and demands $7k. Have texts as proof. What can I do?

I purchased a 2010 Land Rover via a private sale. Due to a license suspension, I entered a verbal agreement with a friend to have the vehicle titled and plated in her name temporarily. She agreed to hold the title "in trust" until my license was reinstated. I paid the full purchase price and provided $700 for taxes and fees. She took possession of the vehicle to go to the BMV and has refused to return it. She is now claiming sole ownership because the title is in her name. She has made multiple written demands for money (most recently $7,000) to return my property and has threatened to seize my computer equipment. I have Marketplace messages and bank records showing I am the original buyer, extensive SMS history explicitly showing her agreement to the temporary arrangement, and her subsequent demands for money (extortion). What are my next steps?