GardaÍ are mounting twice daily patrols outside a south Dublin school after a 13-year-old girl was viciously assaulted in an attack linked to the deadly Crumlin/Drimnagh feud that has claimed 16 lives.

Adele Kenny, a mother of five from Monasterboice Road in Crumlin, has been forced to remove three of her children from school following the serious assault of her teenage daughter and ongoing threats from a well-known local crime family.

Adele's brother Ian Kenny (21) was shot in 2007 by one of his closest friends and died in July 2009. His friend Jonathan Dunne was later sentenced to 12 years for the attempted murder.

Dunne carried out the attack at the behest of a well-known local drug dealer, nicknamed Mad Dog, who is emerging as a serious gang leader in Crumlin.

The criminal, who previously worked as a driver for gangland criminal 'Fat' Freddie Thompson, has been involved in a feud with the Kenny family since 2004. Since Kenny was shot, Mad Dog and his associates have been making threats and attacks against various members of the Kenny family.

Two weeks ago, a relation of the criminal – also a schoolgirl – attacked Jade Kenny (13) just outside the school.

The teenager was left with serious facial bruising and extensive damage to her teeth and gums and required hospitalisation. While the attack was being carried out, two others videoed the violent assault on a mobile phone. This practice, where assault is carried out and accomplices record it, is known as 'happy slapping'.

"My daughter was seriously attacked. They danced all over her head outside the school and videoed it. Her face is in an awful state, particularly her mouth and gums. I cannot send her back to that school and I've had to take my two younger children out of the primary school over threats being made against them. I have already buried my brother, I don't want to have to bury one of my kids," Adele Kenny told the Sunday Tribune. A teenage girl was arrested after the assault and the garda investigation is ongoing.

Gardaí now mount daily patrols outside the schools which are situated in the same grounds – St Agnes primary school and Rosary College secondary school – before classes begin and again when students are returning home to prevent further attacks.

Kenny has not sent her daughter back to school and has also removed four-year-old Tori and eight-year-old Clayton from St Agnes primary school.

"My two children in primary school were threatened by other kids over all this. They have shouted things like 'we're going to kill you and your mother like we did to Ian'. The gardaí don't seem to be able to do anything and neither does the school. I have to find a new school now for my children," she added.

The principal at Rosary College did not respond to requests to comment.

Adele said she now has genuine fears for the safety of her children and her extended family over the threats made by Mad Dog and his associates.

"The family who are doing this are out of control. The gardai can't seem to control them. They are terrorizing everyone in Crumlin. They smashed up my sister's car last week. I've passed on threatening messages to gardai they've left on my Facebook page saying things like, 'We're doing to dig up your brother and rape him.' They won't even let us mourn Ian."