Marriott was a 2011 graduate of Westborough High School in Massachusetts. She lived with an aunt in Chester and commuted to the Durham campus. A message seeking comment was left with her parents.
Downey's daughter Nicole, who was Marriott's best friend, described Marriott as a "fun-loving and goofy" young woman who got along easily with others and had a wide circle of friends. She also was a good student who loved animals and science and volunteered at the New England Aquarium in Boston, Nicole Downey said.
"It was a shock to me when I found out she was missing. That was not like her at all," she said. "She was just all around a great person. I don't know why anyone would want to hurt her."
Mazzaglia, who graduated from the University of New Hampshire in 2006 with a bachelor's degree in theater, was active in the arts, performing in several dozen plays and musicals over the last decade in southern New Hampshire.
He also was a martial arts instructor who described himself on websites as having a black belt in karate and being familiar with several forms of martial arts and weapons. And he listed other interests including juggling.
Robert Modee, a friend of Mazzaglia's and a martial arts instructor in Kittery, Maine, said he was struggling to comprehend how Mazzaglia could be charged with murder.
"I don't understand what's going on right now," he told the Foster's Daily Democrat in Dover, N.H. "I'm completely floored with all this."
Mazzaglia was in custody Saturday and could not be reached. It was unclear whether he had a lawyer.