The Tokyo High Court on Thursday upheld the life term meted out by a lower court to a 51-year-old man convicted of murdering a House of Representatives lawmaker inOctober 2002.

Hakusui Ito, described in court as a rightwing activist, was convicted of fatally stabbing Democratic Party of Japan member Koki Ishii, 61, in front of the legislator's house in Setagaya Ward, Tokyo, on Oct. 25, 2002. He turned himself in to police the next day.

In June 2004, the district court sentenced him to life. Ito, who had pleaded guilty, appealed, saying the ruling, which stated the true motive of his actions remained unknown, misinterpreted the facts.

Ito claimed he killed Ishii due to a personal grudge. He said the lawmaker had turned down his plea to return a favor, with the defendant having raised 27 million yen for Ishii early in the politician's career.

In handing down Thursday's ruling, presiding Judge Kenjiro Tao said "there is nothing that backs up (Ito's) testimony."

He said the defendant's claim that he had handed Ishii 27 million yen was itself doubtful as there was no proof.

Ishii's family had voiced suspicion that there was a wider motive behind the murder, especially given that he had been actively involved in exposing matters such as political corruption and loan-sharking.

Ishii's 33-year-old daughter, Tatiana, voiced disappointment over the verdict.

"The bottom line is that this case ended leaving many unanswered questions," she said. "We still don't know why Ito murdered (my father)."

Natasha, Ishii's 60-year old Russian widow, tearfully spoke of her late husband.

"When my husband passed away, a part of me died with him," she said. "I would like to live in a society where a person who purposely takes the life of another has no right to live."