Lee Jae-myung (Yonhap)

A Busan court sentenced the 67-year-old man who attacked main opposition Democratic Party leader Lee Jae-myung with a knife in January to 15 years in prison Friday.

The court found the defendant surnamed Kim guilty of attempted murder and violation of the Public Official Election Act, for his Jan. 2 attack against Lee during his visit to the city. Kim had posed as a supporter to approach Lee, but then stabbed him in the neck.

He told investigators that the attack was to prevent Lee from becoming president. The attack, which took place just three months before the April 10 general election, left the opposition leader Lee hospitalized for eight days with substantial damage to his jugular vein.

"Attacking the victim just because he had different political views than oneself is an act of destruction that seriously undermines the representative democracy and the election system, which should be carried out by the free will of the people in accordance with the constitution, the law and due process," the court said in its verdict. It called Kim's crime a "a severe violation of the social consent and trust in the fundamental order of democracy."

Investigators found that Kim had followed Lee around for nine months before the attack, and he practiced stabbing the neck with clear intent to kill.

Kim has said that he has contemplated his actions in confinement, and even though his political views remain unchanged, he felt deeply sorry to Lee as a person.

Despite Kim's apologies, the court questioned his sincerity, given his attitude in defending his criminal motive to the legal and investigative authorities.

The court also found an acquaintance of Kim guilty of aiding and abetting a murder, sentencing them to a prison term of one year and six months, suspended for three years. The court said the person was well aware of Kim's plans, having delivered Kim's messages, including the crime motive, to his family via mail.