Prosecutors are seeking a life sentence for a 22-year-old man who has pleaded guilty to fatally stabbing his former girlfriend last October in a high-profile stalking-murder case in Mitaka, western Tokyo.

The court is set to issue a ruling Friday on Charles Thomas Ikenaga, who pleaded guilty to murdering the 18-year-old high school student. Ikenaga reportedly began stalking her after she rejected his pleas to resume their relationship.

"It is extremely cruel that he chased the student who was running away and stabbed her many times on a street while straddling her," a prosecutor said during a Tuesday session at the Tachikawa Branch of the Tokyo District Court.

The prosecution added that Ikenaga also "insulted" the victim as he posted online shortly before and after the murder private pictures of the victim taken while they were seeing each other.

The victim's mother, who attended the hearing, told the court she wants Ikenaga to face execution.

"The defendant has made no apology," she said. "He should pay for his crime by receiving capital punishment."

Ikenaga told the court: "I thought I was rejected totally" by the victim. "We could have broken up more amicably. I regret" how things turned out, he said.

Ikenaga and the victim met online around July 2011 and started a relationship that December. The victim sought to end the relationship in the fall of 2012, after which Ikenaga began stalking her, according to the police investigation.