Cho had previously been diagnosed with selective mutism and severe depression. During much of his middle school and high school years, he received therapy and special education support. After graduating from high school, Cho enrolled at Virginia Tech. Because of federal privacy laws, the university was unaware of Cho's previous diagnoses or the accommodations he had been granted at school. In 2005, Cho was accused of stalking two female students. After an investigation, a Virginia special justice declared Cho mentally ill and ordered him to attend treatment; however, because he was not institutionalized, he was allowed to purchase guns. The shooting prompted the state of Virginia to close legal loopholes that had allowed individuals adjudicated as mentally unsound to purchase handguns without detection by the National Instant Criminal Background Check System (NICS). It also led to passage of the only major federal gun control measure in the U.S. since 1994. The law strengthening the NICS was signed by President George W. Bush on January 5, 2008.