The parents of Lindsay Ann Hawker, the English teacher from the U.K. who was brutally murdered six months ago, have expressed frustration that her killer has not yet been apprehended.

“This man must be caught. We are very frightened that he will offend again,” her father, William Hawker, said by telephone from England. He was referring to suspect Tatsuya Ichihashi, 28.

“I am sure that the Japanese police are doing their best,” Hawker, 54, said, while urging them to provide the family with more information on the progress of the investigation.

“Initially, we had information coming from the police and we felt that we were more involved with the case,” he said. “Now, we only receive a weekly report on what the police have done and where they have searched.”

Back in March, Ichihashi got away from officers who were sent to his home to question him about the missing girl. On checking Ichihashi’s apartment, police found Lindsay’s body in a bathtub filled with sand on the balcony.

Police have received more than 2,000 reports on him from 45 of the 47 prefectures and sent officers to roughly 20 prefectures so far. But they have developed few concrete clues on his whereabouts.

Lindsay Ann Hawker website