Behind Liberty Bell Bomb Threat: Ex-ASU Professor? No explosives found in Carlos Balsas' backpack after alleged threat By Evann Gastaldo, Newser Staff Posted Jan 28, 2013 12:13 PM CST 11 comments Comments A tourist visits the Liberty Bell during a winter storm, Saturday, Dec. 19, 2009, in Philadelphia. (AP Photo/Matt Slocum) (Newser) – A former Arizona State University professor went to visit the Liberty Bell in Philadelphia Saturday and told security personnel who were examining his backpack, "I have explosives in there," police say. Carlos Balsas then left his backpack there and walked away; he was arrested nearby after a brief struggle. Meanwhile, the bomb squad arrived at the Liberty Bell and found Balsas' backpack tested negative for explosives. He's been charged with numerous offenses including bomb threats and terroristic threats, the Philadelphia Inquirer reports. For once, we don't have a neighbor talking about what a nice guy Balsas seemed like: Christine Darling tells My Fox Phoenix that Balsas had complained about a leak seeping from her townhouse into his below, and that he would "scream" at her—but refused to let her contractor into his home to fix it. "I was actually so scared I called the Tempe Police Department," she says. Balsas, 41, taught urban planning at ASU from 2004 to 2011, and he once led a movement to refurbish the Arizona state Capitol.