Prosecutors said Tuesday a psychologically distressed college student was indicted for murdering his former high school teacher.

The suspect, identified only by his surname Yu, is charged with stabbing to death his former guidance counselor, who remains unnamed. According to prosecutors, Yu was suffering from erotomania. Sufferers of the psychological disorder falsely believe that another individual is in love with them.

Yu first met his alleged victim in 2009 during his second year of high school. After he expressed his romantic feelings to the counselor, she clearly told Yu that she did not reciprocate his emotions, according to prosecutors.

After dropping out of high school in December 2010, Yu began stalking his former teacher. In February 2011, Yu told school authorities that he and the counselor were in a romantic relationship. The teacher denied Yu’s claims, and threatened to contact the police.

Later that month, Yu accosted the woman in front of her home, armed with a steel pipe. He attempted to rape and murder her before deciding otherwise.

In 2013, Yu heard the counselor had become engaged. After sending around 400 emails with death threats, Yu confronted the victim at her workplace on Dec. 18 last year, stabbing her about 10 times, according to law enforcement officials.

According to the Journal of the National Medical Association in the United States, patients suffering from erotomania develop “an elaborate delusional process” about another individual being infatuated with them. The condition can persist for several years.

By Jeong Hunny (hj257@heraldcorp.com)