This is the process that investigators are now focusing on.
At the two sites where investigators have focused their attention in recent days, there was little activity today.
A spokesman said the special investigators focus on possible criminal activity.
Investigators are focusing much of their attention on this general area, rows 21 through 25.
Why did investigators focus on one person over another?
Investigators also focused today on what the agency had done to watch for hazardous materials.
Investigators are focusing on possible human error in Friday's crash.
Investigators stepped up surveillance in the area but did not focus on it exclusively.
The more serious problems might have involved a transmission line in Cleveland that investigators were focusing on.
By today, they had finished digging through more than two of the three acres on which investigators have focused.
