I heard some followup coverage this morning. The employee killed was the intended target of the bomb. This was a hit not a terrorist act. If terrorism was the intent, the bomb would have been inside a casino not in the parking garage and set to explode only when the employee picked it up.
As to your statement, "If terrorism was the intent, the bomb would have been inside a casino not in the parking garage and set to explode only when the employee picked it up," perhaps it was a "trial balloon" i.e. the 1993 bombing of the World Trade Center (in the parking garage.)