By Chris Hogg
BBC Tokyo correspondent
Japanese police have created images of how the suspect may look now
It is nearly a year since the badly beaten body of Lindsay Ann Hawker was found covered in sand in a bath at a Japanese apartment.
But the man suspected of her murder has still not been found.
The plain-clothes policeman in front of me looks uncomfortable. He is nervous. This is not what he wants to be doing, answering questions from a journalist. He wants to be back at his desk.
Shinya Oguma is the man in charge of the hunt for Tatsuya Ichihashi, who police believe attacked, tortured and then killed British schoolteacher Lindsay Ann Hawker, and buried her in a bathtub full of sand.
The case shocked people here in Japan. It reminded people of the murder of another young British woman, Lucie Blackman, a few years earlier.
Lindsay Hawker's body was found in a sand-filled bathtub
This time there was one suspect - the man who had chased Lindsay one night on her way home from the station, pestering her to teach him English, leaving his name and number at her flat.
Tatsuya Ichihashi appeared to be the last person to have seen her alive. CCTV footage from a cafe showed Lindsay with a man who matched his description.
Her remains were found buried on the balcony of his apartment, and when police arrived looking for her, he ran away from them and escaped.
Lindsay Hawker's family, from Brandon, near Coventry, must have thought that with the huge amount of publicity the case attracted in Japan it would not be long before the suspect was arrested.
A year later though they are still waiting for justice for their murdered daughter.
When Lindsay's father, Bill, came to Japan he said Tatsuya Ichihashi "brought shame to this country", Detective Oguma says.
"All of us working on this investigation have engraved his words on our hearts. We want to help Lindsay to rest in peace, we never forget that and so we carry on."
The detective has been in the force for 28 years. This case he tells me is "special, unusual".
He started with 100 officers. That was increased to 140, a month after Lindsay's body was found. Usually a murder investigation like this would be handled by about 80. It is a reflection of the high priority the case has been given, Det Oguma says.
He says they have received more than 3,000 pieces of information mostly e-mails and phone calls from the public, but the reality is that none of these seem to have moved the investigation further forward.
Paul Dingwell is helping to publicise Lindsay's case
The police still get possible sightings now, a year after Tatsuya Ichihashi went missing. Two or three have been from abroad, from Hong Kong or Singapore. Every one is followed up.
I followed his officers as they went from building to building in central Tokyo, to bars, to clubs, to hotels showing people a photograph of the suspect.
This month they have even released a computer generated image of the man they seek, showing what he might look like if he were dressed as a woman to hide himself, or with dyed hair.
The practice of showing people photographs of a suspect with possible disguises is not unusual here. But why has he not been apprehended?
"When an offender is determined to run and hide," the detective says. "It's hard to find him. Ichihashi didn't have a phone or a credit card, anything that might make him easier to trace."
He does not want to be drawn on what might have happened to the man he is hunting. He does not want to risk tipping him off about how much or how little the police actually know.
There are different theories - that he is being protected by Japanese gangsters the Yakuza or he is hiding in one of Tokyo's seedier neighbourhoods.
He may of course have killed himself, although the police do not think so.
Lindsay Hawker's family have expressed their frustration at the lack of progress in the police investigation, although they say they have no alternative but to keep faith with the Japanese police.
Her friends too are frustrated.
Recently they gathered on a Sunday to hand out fliers appealing to the Japanese people for any information that might lead to the arrest of Tatsuya Ichihashi.
Paul Dingwell, a fellow teacher who knew Lindsay well, says the fact that this man has been able to disappear reflects badly on the Japanese.
"They should feel some kind of guilt that this has happened in their country, to someone who came here to help," he says.
"If someone is hiding him they are just as guilty as he is, if not more."
The police remain hopeful that as time goes on, their suspect will relax and perhaps make a mistake that will lead to his capture.
For now though the trail appears to have gone cold. If Lindsay Hawker's killer is hidden in Tokyo, he is hidden well.