The Tokyo High Court on Friday increased a man's 15-year prison sentence for killing the manager of a JR Tokyo Station convenience store, handing him a life term.

In handing down the ruling on 35-year-old Hidekazu Omori, presiding Judge Atsushi Semba said, "Even though he turned himself in, this was not a case in which the criminal would not have been identified otherwise. A 15-year sentence was too lenient."

Both the prosecution and defense teams had appealed the 15-year term handed down in January by the Tokyo District Court.

Semba described the murder of store manager Masahiko Okeda, 33, on July 21 last year as a heinous crime that was committed with the selfish motive of trying to evade arrest and imprisonment. The victim had chased after Omori, who had shoplifted 550 yen worth of food.

The judge rejected the defense team's claim that Omori had no intention to kill. Semba said the defendant stabbed Okeda knowing that he would cause fatal injuries.

At a news conference after the ruling, Okeda's father said, "My son will never return, but (the court) acknowledged his courageous act. . . . The lower court sentence was too light, and thus unacceptable. Life imprisonment is only natural."

Semba added that Omori had committed the crime while serving a suspended sentence for another offense.