The families of two British teenagers who had acid thrown at them in Zanzibar have expressed their frustration at the “lack of urgency” to identify the men that did it.
Londoners Kirstie Trup and Katie Gee, both 18, were nearing the end of a month-long volunteering holiday teaching English when they were targeted by two men on a moped on 7 August.
Their families called on the UK Government to apply more pressure to the Tanzanian authorities.
Police in Zanzibar have already interviewed several people, including eyewitnesses, and are believed to have identified a possible culprit.
However, Miss Trup’s father Marc told the BBC's Radio 4 Today programme that there is still confusion over how to get a photograph of the suspect to the young women for identification.
He said: "The photograph cannot be sent in the correct format that is acceptable by Interpol, or the British authorities, and as a consequence of that nobody has seen the photo."
Doug Morris, the partner of Miss Gee's mother, said: "If the Foreign and Commonwealth Office are as committed to helping to bring these people to justice on behalf of two British citizens, then you would expect them to move hell and high water to do that.
"And there just doesn't seem to be any sense of urgency to conclude matters.
"If they mean what they say, if it's important for them to find the perpetrators of this attack, this crime, and bring them to justice - as they said at the time - then they should be assisting us in every way that they possibly can.
"Everybody is trying to sort of give the impression that they are dealing with this, and we are served platitudes on a bi-weekly basis.
"This crime can't go unpunished, for the girls' sake as much as anything else. What sort of message is that, that you can do something horrific, you can do something horrible, and you can get away with it?
"We don't want it to drag on and on, we want justice done and we want justice done now."
The families said they have “no idea” why the girls were attacked, as they were behaving respectfully and were dressed modestly, in accordance with the local customs of the predominantly Muslim country.
Mr Trup added: "I suspect the Tanzanian authorities don't take the Foreign Office remotely seriously. We want the judicial system to work properly.
"I would like to see whoever threw that acid brought to justice. I don't blame the country, I don't blame the religion. I blame the person. He needs to be brought to justice.
"Above all, the girls want to know why he did it and we would like to know why he did it. Was it racial, was it a religious thing? We have no idea why this person did it."
He said his daughter was now recovering from her injuries: "Kirstie is doing well, she's moved to university. She seems to be progressing well mentally and physically. Kirstie is still having treatment at the local hospital. She has to wear a pressure garment over her burns, which she has to wear 23 hours a day for one whole year.
"She goes regularly once a week to hospital for continual physiotherapy on her burns, but she's progressing well physically and mentally she appears to be moving well. She has difficult times."
Mr Morris said: "Katie is remarkable. She's very strong mentally and just coping with the process of healing."