What will happen if I stole $1,535 from my employer and admitted to it and left the company?

Whether you talk to the detective or not, you will likely be charged with a crime. You already made an admission to the employer regarding your actions. If this is your first time in trouble with the law, you will likely be treated as a first-timer. Before you waltz yourself voluntarily into the police station and do their job for them, you might, read that as you really should, decide to contact a criminal defense attorney first.