Devastated friends of the American woman stabbed to death in London have paid tribute to the retired special education teacher, hailing her as an "inspiration".
Darlene Horton was just hours away from returning to her home in the small Florida city of Tallahassee with her husband when she was killed on Wednesday night.
Her partner Richard Wagner, a psychology professor at Florida State University (FSU), had been teaching summer classes that had ended that day. It is understood university officials have flown to London to support him.
Friends of the couple and their two grown up children back home in the US have described a "fine family" who play a big role in the university's psychology faculty and are highly regarded within their local community for their philanthropy.
Neighbour Jane Marks told the Tallahassee Democrat Horton was "absolutely lovely. Just one of the nicest, sweetest family-focused people who is very happy in her space and place".
The couple are understood to have supported the Tallahassee Memorial HealthCare Foundation - a non-profit community healthcare organisation - as well as a theatrical group and a humane society.
Richard had been travelling abroad to teach for several years accompanied by his wife, who began her career in education in the 1980s.
A former colleague told the newspaper Horton had a "vibrant personality" and "loved her students and was eager to do whatever she had to do. She would go beyond the extra mile".
Janet Kistner, a colleague of Horton's husband at FSU, said she was a keen tennis player, and "just a bright, inquisitive person".
She added: "We are a faculty that knows everybody as family. It's very much a loss for all of us."
Mary Alice Linzy, a friend of Horton's for 15 years, described how she saw reports of Wednesday night's tragedy on Facebook, before her identity was revealed.
"We're just a small little town here and we have this small tennis community," she told the newspaper.
"I'm just going to miss her so much. She was an inspiration for me.
"Every time I step on the tennis court now I'm going to be thinking of Darlene. I just cannot believe it."
A 19-year-old Norwegian of Somali heritage was arrested on suspicion of murder after the attack that also left two women and three men injured, one seriously.