A man in his 20s has been sentenced to a year and six months in prison for attacking a police officer with a knife, for what he thought was "insincere response" from investigators.

The defendant was found guilty by the Seoul Northern District Court of both obstruction of official duties and special obstruction of public duty, which is applied when the crime involves the use of a dangerous weapon.

"This crime is very dangerous in both its means and the results, and the defendant has committed similar crimes consecutively in the space of two to three months," the court said in its verdict. The court did take into consideration that the defendant has no previous criminal record and that he has been suffering from episodes of epilepsy for a long time.

The court punishment was for his attack on a police officer with a knife on Jan. 22, and a separate assault of other officers that took place on Nov. 2. The defendant said he attacked the police because was unsatisfied with the way police handled his dating violence case last year against his girlfriend.

He told investigators that he had inquired about the case, but the officers gave "an insincere answer."

In November, he went to a substation of the Seoul Seongbuk Police Station, looking for officers that handled his case. He launched a verbal and physical abuse on multiple officers, for which he had been on trial for at the time of the January attack.

At around 2:32 p.m. on Jan.22, he went to the same substation and attempted to set fire to official documents. He attacked with a knife a 49-year-old officer who attempted to stop him, resulting in an injury that required three weeks of medical treatment.