Tatsuya Ichihashi, who has admitted the killing but denies it was murder, evaded police for more than two-and-a-half years despite huge resources dedicated to the case.
More than 140 investigators worked on the manhunt but the suspect remained at large and some believed he had committed suicide.
In fact, he had spent two years and seven months on the run and changing his appearance to help him stay below the radar.
Now, more than four years after Miss Hawker's death, he has gone on trial accused of her murder.
Ichihashi fled barefoot from his apartment when police arrived searching for the 22-year-old in March 2007.
She had been in Tokyo teaching English and CCTV showed the pair in a coffee shop as he apparently had a lesson.
Miss Hawker, a former Leeds University student, went back to her student's apartment in Ichikawa, Chiba, and was never seen alive again.
A final entry on her Facebook page on March 20 had said: "Love u lots dont worry abt the gut [guy] who chased me home, its jus crazy Japan. miss u xxx."
The Briton had left details of her appointment, which led police to Ichihashi's flat. They found her body dumped in a sand-filled bath tub on his balcony.
Her hands and ankles had been tied with plastic cord used to bind plants and she was totally buried but for one hand.
Somehow the Japanese man managed to slip away, sparking a nationwide manhunt that humiliated the police.
While he was on the run, Miss Hawker's family battled to keep the case in the public eye and travelled to Japan several times to raise its profile.
Tens of thousands of posters were handed out showing how Ichihashi would look in drag or with dyed hair but there were no confirmed sightings for 32 months.
Eventually, he was caught in November 2009 at a ferry terminal in Osaka trying to catch a boat after a passer-by recognised him.
He had been lying low, working on construction sites and using the name and address of a dead man, Kosuke Inoue, from the same area.
In a book written from prison, he claimed he also went on a Buddhist pilgrimage, read all the Harry Potter books and lived off wild fruit and snakes.
He recounted how he had scissored off his lower lip, dug two moles from his cheek and even gave himself a nose job to try to hide his true identity.
But when he sought further cosmetic surgery, staff became suspicious and contacted police who released pictures of his new look.
Workers recognised their former colleague and called detectives and he was finally arrested and charged.
Ichihashi admitted the killing in his book, which he said he wrote as a "gesture of contrition" for the crime.
He also wrote a letter to the Hawker family, apologising for his "evil" actions and saying: "I will carry my cross until the moment of my death."
The Briton's parents refused to read it because Japanese criminals can often receive lighter sentences if victims' relatives accept their apology.
The Hawkers are now in Japan for Ichihashi's trial. Mr Hawker said: "I'm here to get justice for my daughter. It's been a long time coming."
Ichihashi denies he intended to kill the 22-year-old but if he is convicted of murder, he could face the death penalty.
More than 140 investigators worked on the manhunt but the suspect remained at large and some believed he had committed suicide.
In fact, he had spent two years and seven months on the run and changing his appearance to help him stay below the radar.
Now, more than four years after Miss Hawker's death, he has gone on trial accused of her murder.
Ichihashi fled barefoot from his apartment when police arrived searching for the 22-year-old in March 2007.
She had been in Tokyo teaching English and CCTV showed the pair in a coffee shop as he apparently had a lesson.
Miss Hawker, a former Leeds University student, went back to her student's apartment in Ichikawa, Chiba, and was never seen alive again.
A final entry on her Facebook page on March 20 had said: "Love u lots dont worry abt the gut [guy] who chased me home, its jus crazy Japan. miss u xxx."
The Briton had left details of her appointment, which led police to Ichihashi's flat. They found her body dumped in a sand-filled bath tub on his balcony.
Somehow the Japanese man managed to slip away, sparking a nationwide manhunt that humiliated the police.
While he was on the run, Miss Hawker's family battled to keep the case in the public eye and travelled to Japan several times to raise its profile.
Tens of thousands of posters were handed out showing how Ichihashi would look in drag or with dyed hair but there were no confirmed sightings for 32 months.
Eventually, he was caught in November 2009 at a ferry terminal in Osaka trying to catch a boat after a passer-by recognised him.
He had been lying low, working on construction sites and using the name and address of a dead man, Kosuke Inoue, from the same area.
In a book written from prison, he claimed he also went on a Buddhist pilgrimage, read all the Harry Potter books and lived off wild fruit and snakes.
He recounted how he had scissored off his lower lip, dug two moles from his cheek and even gave himself a nose job to try to hide his true identity.
But when he sought further cosmetic surgery, staff became suspicious and contacted police who released pictures of his new look.
Workers recognised their former colleague and called detectives and he was finally arrested and charged.
Ichihashi admitted the killing in his book, which he said he wrote as a "gesture of contrition" for the crime.
He also wrote a letter to the Hawker family, apologising for his "evil" actions and saying: "I will carry my cross until the moment of my death."
The Briton's parents refused to read it because Japanese criminals can often receive lighter sentences if victims' relatives accept their apology.
The Hawkers are now in Japan for Ichihashi's trial. Mr Hawker said: "I'm here to get justice for my daughter. It's been a long time coming."
Ichihashi denies he intended to kill the 22-year-old but if he is convicted of murder, he could face the death penalty.
