The father of murdered Briton Lindsay Ann Hawker said Monday it was "disgraceful" that police did not arrest suspect Tatsuya Ichihashi when they first called at his apartment in Chiba Prefecture following his daughter's disappearance.

Her mother, Julia, also said she was "disappointed" with the police investigation, claiming they failed to follow up leads and keep the family fully informed of developments.

Due to the lack of progress, the family has now set up a global e-mail campaign to boost awareness about their daughter's murder and the hunt for the suspect.

The naked and beaten body of Hawker, a 22-year-old English teacher, from Coventry, central England, was found in a sand-filled bathtub on the balcony of Ichihashi's apartment in Ichikawa on March 26.