As
@The4TierBridge stated, it is a synonym for tracking down. The term is based on the usual method of Border Patrol tracking-
Identify the tracks "sign", then identify where the drug back packers or illegal crossers are likely going. The agent then "jumps" to the next spot where there is likely to be sign (a "cut"). The agent then "cuts the sign". Once the sign is confirmed, the agent then jumps to the next likely "cut" and attempts to "cut the sign" again.
The jumping allows for faster tracking than the direct tracking method. And.... experienced "sign cutters" can compensate for tricks like trying to brush sign out, walking backwards, walking in circles etc. They can also spot, then jump on miniscule amounts of "sign".