Taipei knife attack determined 'expressive crime' as investigation ends

Taipei, Jan. 15 (CNA) Prosecutors have concluded their investigation into a deadly knife attack that took place in Taipei in December, saying they were unable to clearly determine the attacker's internal motive but classified the incident as an "expressive crime."

The 27-year-old suspect, Chang Wen (張文), killed three people and injured others on Dec. 19 at MRT Taipei Main Station and near MRT Zhongshan Station.

He died after falling from the roof of the Eslite Spectrum Nanxi department store near MRT Zhongshan Station.

The Taipei District Prosecutors Office said Thursday they closed the case with a nonprosecutorial disposition since the sole suspect had already died.

Forensic evidence and Chang's behavior pointed to intentional suicide, according to prosecutors.

Investigators found no evidence that Chang, who was unemployed and estranged from his family at the time of the attack, acted with accomplices or as part of a criminal syndicate.

Financial records showed no unexpected funding sources and communication records and social media activity did not indicate coordination with others, while surveillance footage and transit card and YouBike data showed Chang acted alone, the prosecutors found.

Chief prosecutor Tseng Yang-ling (曾揚嶺) said investigators classified the case as a "highly planned expressive crime" based on evidence gathered during the investigation and expert assessments, but that Chang's internal motive could not be directly determined.

Chang had a "repressed personality" and was withdrawn from society, they said.

Chang made an attack-plan document on Oct. 5 which he edited more than 60 times before the attack, with specific Taipei Metro locations identified, prosecutors said.

His actions demonstrated intent to kill and involved violations of the Firearms, Ammunition, and Knives Control Act and the criminal code, they said.

Investigative findings described Chang as exhibiting antisocial personality disorder, with the suspect determined as having limited social interaction and poor interpersonal relationships.

The Taipei District Prosecutors Office said digital forensic analysis of items including Chang's mobile devices, as well as a review of his online activity, showed he had searched for violent content thousands of times.

Prosecutors said Chang had searched the internet for information about previous random attacks, including 512 searches related specifically to the 2014 Taipei Metro attack.