Police have referred a man to the prosecution Tuesday on charges of slashing a random neighbor to death with a Japanese longsword last week.The 37-year-old assailant, surnamed Baek, brandished a 75-centimeter Japanese blade at the entrance of his apartment complex in Seoul's northern Eunpyeong district on July 29 and killed the neighbor, who was smoking outdoors at the time.The victim, a 43-year-old father of two sons aged 4 and 9, did not know the assailant personally.During the police investigation, Baek said he committed the crime because he believed the victim was a spy shadowing him.On his way to attend a court hearing on an arrest warrant sought for him last week, Baek also denied he was in a state of mental vulnerability, and said he was in his right mind when he committed the crime.Police said Baek tested negative in a brief reagent test, and they have requested the National Forensic Service for a detailed examination.Source: Yonhap News Agency