TOKYO - The mother of Japan's only suspect in the murder of a 22-year-old British woman made an emotional plea on television Tuesday, urging her fugitive son to turn himself in to police.

Tatsuya Ichihashi, 30, is wanted in connection with the killing of Lindsay Ann Hawker, an English-language teacher found dead in a sand-filled bathtub on the balcony of his apartment near Tokyo in March 2007.

Police say he underwent plastic surgery to alter his appearance and have released post-operation photos of the man, who is believed to have worked on an Osaka construction site for more than a year until last month.

Hawker's family have repeatedly visited Japan and voiced frustration at police for failing to catch the suspect. Police have since raised a cash reward for information leading to his arrest to more than 100,000 dollars.

As Japan has eagerly followed news about the manhunt, a woman identified as Ichihashi's mother has made an emotional appeal to the man on the run, speaking on the private Fuji television network.

"It's mum, Tatsuya," said the woman in an audio message. "Dad and mum have decided to speak about our feelings, although we know you won't like this."

She said the parents had felt happy when they heard their son had been working diligently and had told colleagues he wanted to be good to his parents.

"If so, please go to Gyotoku police station and tell them the truth. Please," the woman said in a sobbing voice.

Police in Gyotoku on the outskirts of Tokyo are in charge of the case.

Investigators now believe Ichihashi was employed as a construction worker in the western prefecture of Osaka for 13 months until October 11 this year, media said.

A former boss of Ichihashi meanwhile told the private TV network Asahi that he was "very diligent and such a nice kid," adding that "He was aiming to save one million yen (11,000 dollars)."

Other media reports said Ichihashi had made enquiries about how to obtain a Japanese passport, suggesting he may have planned to flee the country.