Would the police issue a warrant for someone, after already having that person at the police station for questioning, after about five days??

I was accused of taking and using a co-worker''s credit card. They have a girl on camera that favors me, and it just so happens that my boyfriend is from the same neighborhood that my coworker lives in and does bootleg cab trips in the neighborhod. So the police has my car on camera and is trying to blae me for the crime. They state the victim stated that it was me in the picture, and they called my moither in so she can i.d. me in the pic. Tthey stated that if I did not confess to the crime or have my bf come in they will charge me and issue a warrant. Two days later my bf came in and issued a statement saying that he took someone else to use the cc, and let that person use the car a few of days before. After giving his statement, the officer threatened to charge him with complecity, but let him go. The next day, the detective called my mother and told her that I need to come to the station to turn myself in or he will issue a warrant for my arreet. I did not turn myself .