Where is the "suspicious activity" in Presidum Commons?

Question

I ran across two feuding fellows and picked up a new mission called "Citadel: Cerberus Retribution" in my journal. I'm supposed to go to Presidium Commons and look for an "suspicious activity."

When I go to the Commons, I don't notice any such "activity." I was expecting something pretty obvious such as people working on something or a mob of people just lurking around, but everything seems to be quiet. This leads me to my question...

What and where is the actual "suspicious activity" that I'm supposed to interact with to proceed with the Citadel: Cerberus Retribution mission?

Answer 1

You need to go to the C-Sec Outpost in the Presidium Commons area and speak with Captain Aaron Sommers. You'll find him just inside the doorway, sitting on the left hand side. Speaking with him allows you to complete the mission.

There is a waypoint that appears immediately after speaking with the people who start the mission. It should lead you directly to him.

Answer 2

Head inside of the C-Sec office, and talk to the man on the bench, who will say he is plotting to kill some people. Persuade him not to and you will complete it.