Looking for a thriller

Ok since I found a movie I was looking for here, I think there is a pretty good chance to find a help for another movie. This is going to be even more difficult than the previous one, because I saw it long time ago when I was very young on TV. I remember that there were two main characters - a man and his wife. They were some kind of university professors or at least one of them. They were helping the police with a bomber who was using cryptic notes and riddles for his next targets. This is all I can remember. The movie is probably from the 90's.

Arlington Road?

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It's quite similar, but it's not this one. The bomber was not their neighbor.

Blow away with jeff briges??? Maybe

Might be Critical Assembly - male & female college students

I think it's none of the two movies.

It’s unlikely to be your film, but still, check out Copycat (1995).

Much older
The mad bomber
Or
Live wire


Both also involving bomb have a look