Lupe Cantu remembers exactly how it all went down. "I just finished cleaning up everything and I was restocking on the chips... when all of the sudden this lady called me and I turned around," he recalled about Monday's incident. "She was basically telling me that there was a man who had exposed himself here in the library." The alleged victims are two 7-year-old twin girls. Instincts kick in. Lupe takes off after the suspect. "I wanted to see if he got into any cars," he told Action 4's Ryan Wolf. Once outside, he immediately gets some help from a good Samaritan. "He's like the guy took off down this way," Lupe said. He and his helper give chase on foot. "So we came back here to the alleyway," Lupe said while walking behind the library. "I went a little farther down that way to see if the gentleman took off that way. He was not there. When I came back, the guy that was helping me, he points and tells me there's a guy hiding in the trees." That guy is later identified by police as Gregorio Gonzalez, Jr. of Harlingen. Lupe has no idea at this point that Gregorio is a registered sex offender out of Kentucky. "I see some movement in the bushes," Lupe said next. But the closer he gets, the faster the suspect flees. Lupe devises a plan to fan out. "Just to make sure the guy didn't run around in circles around the building," he explained. "The guy that helped out took to the left side and I took off to the right side. I ended up running across Sam Houston. I had to stop a couple of cars. I managed to catch up to the guy." What happens next, Lupe credits to his two years of experience as a library aide at the San Benito Public Library. "He turns around and asks me, 'Why are you chasing me?'" the city worker recalled being asked. Lupe says he used his soft-spoken manner to convince the 60-year-old to turn himself in. "I thought you all were chasing me cause you were going to beat me up," Lupe said the suspect told him next. "So I tell him, 'Oh no sir, it's just because you match the description... I didn't mean to scare you.'" They walk back to the library together. Lupe gives the man a water bottle. The hunt is over. "They put the handcuffs on him and arrested him," Lupe explained once police arrived. "Do you consider yourself a hero?" Ryan Wolf asked. "No," he said. "I would consider the other guy who helped me to be a hero." It's one heck-of-a-story from one-heck-of-a librarian. San Benito city leaders say they plan to have officers do random patrols of the library building. Gregorio is charged with two counts of indecency with a child. His bond is set at $50,000.