In 1stEd, there was the Technical(Forensics) skill (from the season 5 book I think).

In 2ndEd, Forensics is part of the Investigate skill. I like that because it avoids addin a skill. The problem is that Investigate can't be selected as a primary area of expertise for a scientist. That makes the creation of a character who is a CSI (crime scene investigator) problematic and one of my potential player happens to have that concept in mind.

I was thinking of allowing the forensics part of investigate to be selected as primary area of expertise. It wouldn't help searchin for a secret pannel in a wall but it would help when analysing DNA or explosives residues for example.

Normally, I don't hesitate to make such adjustments when I think they make sense but this would be my first B5 game and I'm a bit unconfortable changing the rules before even starting my first game.

What do you think of the idea?
Me, I'd add a Technical (Forensics) skill, allow it to be a primary skill and have done with it :)

It would add a decent circumstance bonus (+4 at least) to any roll made for Forensics to whichever is the higher of the Investigate or Technical (Forensics) skill when used. Basically, you're good at that stuff and have blown skill points on a specific skill rather than a general catchall one.
I'm running a campaign and I'd make that change if a character were interested in this...its really a minor adjustment go for it.

Investigate should really be in the Scientist study list... if we do an errata list for B52E, I'll see about adding it. Certainly, for this campaign, the simplest thing to do is to add it to the list.