A 22-year prison sentence for a man convicted of killing his former teenage girlfriend in 2013 was finalized Wednesday, after both the man and prosecutors opted not to appeal the high court ruling.

The parents of the victim expressed disappointed over the sentence for the stalking-murder case in Mitaka, western Tokyo, saying in a statement, "A 22-year sentence is too lenient for a crime that claimed the life of our daughter who did nothing wrong."

The Tokyo High Court upheld a lower court ruling on Jan. 24, judging that the sentence for Charles Thomas Ikenaga, 24, was fair and there were no grounds for it to be changed.

According to the ruling, Ikenaga killed his 18-year-old former girlfriend at her home in Mitaka on Oct. 8, 2013, by stabbing her in the neck and abdomen with a knife. On Oct. 6 and 8, he posted on a social networking site a link to a website where he had uploaded explicit pictures of her in an act of "revenge porn."

Ikenaga was initially sentenced to 22 years in prison by the Tachikawa branch of the Tokyo District Court in 2014. But the high court repealed the ruling and sent back the case in 2015, saying the district court mishandled the trial by being overly influenced by the act of revenge porn, which had not been included in his indictment.

The prosecutors then indicted Ikenaga over the revenge porn. In the ensuing retrial, the district court in March 2016 gave the defendant the same sentence of 22 years in prison, a ruling appealed by both the defendant and the prosecutors and upheld by the high court.

The parents criticized the decision reached by judicial authorities as deviating "significantly from ordinary people's common sense," even though the case was determined by a panel consisting of both professional and lay judges.