THE teenage daughter of murdered British hostage David Haines has said she has been touched by messages of support since her father was killed by Islamic extremists.

Bethany Haines, who was said to have been "inconsolable" since her father was kidnapped by militants in March last year while working for an aid organisation in Syria, left a message on a Facebook page set up to call for the release of her father.

It emerged on Saturday that Mr Haines, who grew up in Perth, had become the latest hostage to be beheaded by the Islamic State extremist group, which is in control of large swathes of Syria and Iraq. The group posted a video of the moments before and after his death online and said his murder was a response to a pledge by Prime Minister David Cameron to supply arms to opponents of the militants.

Bethany, 17, wrote: "Hi, I'm David's daughter who lives in Perth I was really touched by the messages of support during this hard time I know my dad would be really touched and grateful."

Five days ago, before she learned of her father's death, she wrote in an online post that her father "means everything" to her.

When asked seven months ago who had been the biggest influence on her as a child, she responded: "My Daddy" and in an earlier message she said he knew her "better than anyone else" and described him as her "hero".

Mr Cameron has described the murder of Mr Haines as "an act of pure evil" and vowed that the UK would "hunt down" his murderers. Mr Haines had a second daughter, aged four, with his second wife and had been living in Croatia before travelling to Syria.

Home Secretary Theresa May, speaking at Harvard University yesterday, expressed her condolences to Mr Haines's family and added: "Our message has to be clear. The United Kingdom, like the United States, will not allow these grotesque acts to stop us from keeping our homelands secure and stopping the march of this brutal ideology."

The intervention followed a special service held at Mr Haines' old school, Perth Academy.

The school's chaplain, Rev Jim Stewart, told students that the Islamic State did not represent the Muslim community. He added: "David was making a difference to people by bringing them hope and help at their most vulnerable time. He truly was an inspiration to his family and to those whom he helped. The men who did these awful things are not 'good Muslims' but are criminals whose ideology is centred on power, money and terror."

Meanwhile, Home Office ­Minister James Brokenshire last night said Mr Haines's murder had "nothing to do with Islam"

Speaking at a mosque in east London, Mr Brokenshire condemned the killing at the hands of Islamic State (IS) and called for more people to speak out against extremism. He said: "We stand together in condemning terrorism and extremism but also in being clear that these have nothing to do with Islam or any other faith.

"As the Prime Minister said, the root of these actions lies in a poisonous political ideology that a small minority support. In contrast, Islam is a religion which is observed peacefully and devoutly by more than a billion people."

Promoting a social media campaign entitled, #notinmyname, Mr Brokenshire said it was "heartening" to see how many people were making clear these acts were "alien" to religion.

Mr Haines has become the third hostage to be beheaded by IS in recent weeks, following the deaths of two American journalists. His killer, speaks with a possibly London accent and has been dubbed Jihadi John.

In the video posted by the terror group depicting Mr Haines's murder, it was warned that another British citizen, Alan Henning, will become the next person to be killed.

The taxi driver, from Salford, Greater Manchester, had been delivering aid to help children in the war-torn country when he was captured in December last year.

The 47-year-old , a father of two, appears at the end of the video in which Mr Haines was killed. He has been described by friends as "a big man with a big heart".