You might want to change 'I was involved in' to 'I was the victim of', if that's accurate. I thought you meant you were INVOLVED in the robbery, not involved like being a victim.
I am not sure any of them would realize who had testified against them unless you stood up in court. If the case went to a judge (as they often do these days), it's not likely that they know who testified, or which testimony was more important than the other.
THAT SAID, I'd make sure there were no clues to lead them to you. For example, if you have the same phone number, email or address, or still work at the same place, I think it's possible one of them could find you. I would change phone numbers and emails. As far as if they know your address or place of employ that's harder to change but if you're just renting or doing temp work it would be easy to change those things.
If I was in that sort of situation, I'd go with sensible and reasonable caution and sensible and reasonable efforts to not make it easy to find you.
HOWEVER, THAT SAID, I think that after an armed robbery in which someone died, they are not too likely to do a crime that would so obviously be pointing directly to them, or to do something that would mess with their parole or other forms of out-of-jailed-ness.
Half way houses are used these days for sentencing, and they have varying levels of security. I looked into one a couple months ago and was absolutely shocked at how restrictive it was. I thought they had some sort of picnic there (believing a news story again, which I already know better than to do). It is no picnic in most of those places. Someone is watching every single move.
Usually, if someone breaks the rules, any of the rules, they go back to a higher level of security - jail. Bothering you would mean breaking the rules. And they know that.
If the person contacts you, that most likely is included in 'breaking the rules'. If they contact you, I'd be sure you contact their parole officer or other authority, and let those guys know.
If anyone DOES contact you, I'd advise you to be sure the authorities know, and take advantage of any steps they can take.
Sometimes people come out of jail very bitter and angry. Sometimes they come out thinking they'll be very smart and stay out of trouble 'for a while'. And sometimes they come out and really do not EVER want to go through that again, and decide to stay away from trouble. Some people come out truly believing things will be different but gradually slip back into old habits once they get back in the same environment.
In that case, you might get contacted with an apology for everything that happened. But I think it takes a very unusual person to do that. And if I did get an apology, I'd say, 'thanks so much' and not discuss any personal info, location, name of employer, etc. Even if they are truly sorry the feeling might not last.
