One photojournalist said she was pulled into secondary inspections three times and asked questions about who she saw and photographed in Tijuana shelters. Another photojournalist said she spent 13 hours detained by Mexican authorities when she tried to cross the border into Mexico City. Eventually, she was denied entry into Mexico and sent back to the U.S.

These American photojournalists and attorneys said they suspected the U.S. government was monitoring them closely but until now, they couldn’t prove it.

Now, documents leaked to NBC 7 Investigates show their fears weren’t baseless. In fact, their own government had listed their names in a secret database of targets, where agents collected information on them. Some had alerts placed on their passports, keeping at least three photojournalists and an attorney from entering Mexico to work.