do you think there are other tunnels being dug right now? >> that's actually what our tunnel task force does. the minute we find one of these things we're working on the information coming in and trying to locate the next one. before it turns into the level of sophistication we saw on this one. >> do the people that own the warehouses on the u.s. side know what's going on? or are they fooled as well? >> for the most part their absentee owners but that's one of the things we launched three days before we found this tunnel was an outreach to the otay mesa community and trying to get the business owners to provide another set of eyes and ears. >> we've visited two of these tunnels in past years, you've seen a lot. are you always surprised by just the level of sophistication? the fact they had a railway in this thing is pretty amazing. >> yeah. every time i've been in one i've been surprised by the uniqueness of the tunnel, the construction, the amount of ingenuity that goes into digging these things, into building them and the investment in time and resource. it's very obvious these cartels