5 years ago my dad was killed by a family friend.I was 18 at the time.He was sentenced to 3 years but served 2 during this time he was sending me letters which at the time I decided not to open and just send back to him.Time has passed now and I am finally getting my life back on track,Recently another family member said that she bumped into him and that he has asked to see me.I have his contact detials,. bacically just want to know what you think about me meeting him to see what he has to say or not.half of me wants to but then again I don't know if that will mean I'm taking a step back?? Any advice would be great. Thanks.

A 3 year sentence suggests that it wasn't a deliberate act of murder... we don't know the whole story, and what sort of man this person was at the time.
I would suggest that other family members handle a formal request from him to see you, that it not be in your home or his, and that family be in attendance if and when it happens. Choose family who you feel are wise and who can keep emotions in check. If you are religious, ask clergy to be there too. Plan on a set time limit such as 20 minutes so that it doesn't bog down or escalate or cause you too much distress. Another can always be arranged. Feel free to cut it short at any time, especially if he's just full of excuses, and make sure that family agrees in advance to leave with you the minute you want to.
If he's truly sorry and that's all he wants to say, and doesn't even expect forgiveness, that could be the closure you need, and even the ability to forgive. I agree that it can be a step back or a step forward, depending on what he has to say and how it's handled.
My feeling is that wrongs that can't be righted need to be paid forward. He can't bring your father back but he can devote some of his existence to saving lives of others, through charity and volunteering. If you don't want to see him until he has made some sort of restitution to the world, then have family tell him that.