TOKYO, JAPAN (AFP) - The only suspect in the mysterious killing of a 22-year-old British woman in Japan ate food on Tuesday for the first time since his arrest two weeks ago, police said.

"He completely ate a boxed lunch we served him," said a duty officer at the Gyotoku police station in Ichikawa, outside Tokyo, where 30-year-old suspect Tatsuya Ichihashi is being held for investigation.

In March 2007 Lindsay Ann Hawker, an English-language teacher, was found dead in a sand-filled bathtub on the balcony of Ichihashi's apartment in Ichikawa.

Since his arrest in Osaka on November 10, Ichihashi had accepted only water and green tea. He was reportedly given a nutritional injection at one point.

Later on Tuesday, Ichihashi was moved to a nearby prison that has a detention facility with medical equipment and staff, to check his condition more closely, media reports said.

"He has been advised by his doctor and his lawyer to take food. He may probably have undergone some psychological change," a senior official at the police station was quoted by the daily Sankei Shimbun as saying.

But Ichihashi, who underwent plastic surgery while on the run from police, has remained silent except for providing his name and other basic background information, the reports said.