Mounting desperation in the hunt for the murderer of Lindsay Hawker, the English teacher found dead in a bath of sand, has prompted Japanese police to issue a new wanted poster with the chief suspect disguised as a woman.

A computer-generated image of Tatsuya Ichihashi, 28, shows what he might look like if, after nearly a year on the run from justice, he had begun wearing a woman's wig, red lipstick and make-up.

Another mock-up picture shows how he might look if he had disguised himself with dyed hair and glasses. “It's been almost a year since the incident,” a police spokesman said. “We knew that he might have changed in that time.” More than 30,000 copies of the unusual poster are to be distributed across the prefecture of Chiba as the nationwide search for the killer of Ms Hawker enters its second year without progress.

Mr Ichihashi evaded the police when they arrived at his Tokyo flat in March 2007. There they made the discovery that horrified a nation where violent crime is rare: the naked body of the missing 22-year-old British woman in a bath of sand on the balcony and evidence that she may have been tortured before her death.

From the very beginning, the hunt for Mr Ichihashi has highlighted the weak investigative powers of the Japanese police. He managed to escape from the flat where he lived despite the presence of nine officers at the scene when police came to question him. It has been suggested that he made his getaway without shoes.

An appeal for witnesses yielded several thousand responses from across Japan but none has yet advanced the case. The practice of showing suspects' photographs with a number of possible disguises has a long and generally unsuccessful history in Japan.

One of the biggest hindrances to the investigation is the highly fragmented nature of Japanese policing. The country is divided into 47 administrative prefectures and, although nominally co-operative, prefectural police forces do not readily share information with one another.

The year-long failure to find Mr Ichihashi comes amid growing pressure on the police to undergo dramatic changes to their working practices. The most significant change being discussed would force police to record their interviews with suspects: the historic police reliance on confessions made behind closed doors has been heavily criticised by domestic and overseas human rights groups.

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