Attempting to bribe ATF is not exactly low hanging fruit. Bribing CBP officers and agents is a lot easier and more effective. On CBP's internal website they have a "Trust Betrayed" link that shows the CBP officers that have been charged with crimes. The vast majority of those charged are hispanics who have been caught assisting smugglers in some way.
The scary trend is new hires that seem to have applied for the job for the express purpose of helping the enemy. The cartels are recruiting people with clean records to apply to Customs and BP, knowing that CBP has a big push on to hire minorities.