Taylor Swift "in complete shock" as 3rd girl dies after U.K. stabbing

Taylor Swift posted a message on social media Tuesday expressing her sympathy as a third young girl died after a brutal stabbing attack at a dance and yoga class in the U.K. themed around her music. Five other children and two adults remained hospitalized in critical condition.

The Merseyside Police confirmed Tuesday that a 9-year-old girl had died of her injuries in a regional hospital a day after the attack. Two other girls, aged 6 and 7, died during the Monday attack in Southport, a coastal town in northwest England.

A 17-year-old male was arrested on suspicion of attempted murder and murder, and a knife was seized after the attack, police said Monday. CBS News partner network BBC News reported that the suspect was born in Cardiff, Wales and moved to the Southport area in 2013.

"The horror of yesterday's attack in Southport is washing over me continuously, and I'm just completely in shock," Swift wrote on social media. "The loss of life and the innocence, and the horrendous trauma inflicted on everyone who was there, the families, and first responders. These were just little kids at a dance class. I am at a complete loss for how to ever convey my sympathies to these families."

By Tuesday morning, a group of Taylor Swift fans had raised the equivalent of tens of thousands of dollars to support the victims of the attack and their families, according to BBC News .

The fundraising page says the group is working with the regional Alder Hey Children's Charity, "and raising funeral funds for the two young Swifties who have tragically passed." A number of children involved in the attack are being treated at the Alder Hey Children's Hospital, BBC News reported.

"The idea that those parents are going through hell right now, and the idea they had any financial stress over this breaks our hearts," Cristina Jones, from the U.K. and EU Taylor Swift Facebook group, told the BBC. "We can't make it better in any way, but taking away some stress was definitely a priority for us."