I've been a LEO for close 25+ years. I've done everything from uniform to plain clothes and just returned from S. America working with US SF in the jungles. I can tell you that there is no standard knife that is carried. Since I'm a knife guy, I always tend to ask what my cohorts are toting and I've pretty much seen everything from $5.00 convenience store knives to customs. As a general rule, the most competent guys I work with usually carry Spyderco or Benchmade. That being said, one of the SF guys on my team recently who was pretty much as "tactical-ninja" as they come, was carrying a Gerber Applegate. I can assure you, he was very proficient with it. Another on the team was carrying a Cold Steel Recon and had more real war stories (afgan) than anyone I've ever known but wasn't a knife nut. Another carried a Spyderco Native. Me, in uniform, I carry a Spyderco Karambit non-gun side, Spyderco Matriarch waved in a cargo pocket and a Spyderco Dragonfly in my shirt pocket. Plain Clothes I usually carry a Spyderco Endura with the Emerson Wave. Off duty it can be several but usually the Spyderco Endura Waved, my Hinderer XM-3.5, or ZT 0560. Hiking, any of those three and one of my bush craft knives. Bottom line, some LEOs care what knife they carry but most just grab whatever strikes their fancy or end up carrying what one of their coworkers carry because it looks cool.