What Is an Offender?

A suspect in my world is somebody who has come to the attention of authorities. And there's something suspicious about them in which now authorities are taking a look at as to whether or not they are the offender and can they prove the case. In unsolved cases, you know, let's say it's a hoot on it homicide. I respond out. But when we are talking about an unsolved case, I'm either going to say it's an offender. Some people will say perpetrator. I don't like that term. I always say offender.