A 19-year-old University of New Hampshire-Durham student who has been missing since Tuesday has been presumed dead by police and an acquaintance of the student has been charged with second-degree murder.

Elizabeth "Lizzi" Marriott has been missing since she left the UNH campus to visit a friend in Dover, but did not make it there. According to family and friends, her cellphone was last used at 10:11 p.m. that night.

According to Assistant Attorney General James C. Vera, the police have some very 'credible' information, which has led authorities to declare Marriott is dead.

Though she has been presumed dead by the police, her body has not been found yet and rescue personnel are still in search of the missing body.

The suspect arrested is one 29-year-old Seth Mazzaglia of Dover, who, according to Vera, knew Marriott, but he failed to elaborate on the details leading to his arrest. The Associated Press reports that Mazzaglia is a martial arts instructor, active in community theater.

A native of Westborough, Marriott had been living with her aunt in Chester, N.H., while she took classes at the university. She was a marine biology major who volunteered at the New England Aquarium.

The University of New Hampshire has issued a statement conveying condolences over Marriott's death to her friends and family.

"We were greatly saddened to learn of Lizzi's death and we extend our deepest sympathies to her family and friends," said UNH president Mark W. Huddleston. "Lizzi was a new member of the university community and will be missed in our classrooms. Our focus now will be on supporting our campus community during this difficult time."

University officials have also expressed shock and disbelief over Mazzaglia's arrest as he too was a UNH alumnus who graduated in 2006 with a bachelor's degree in theater.

A candlelight vigil arranged in memory of Marriott Saturday night at Westborough saw hundreds of people coming together to pray for the loss of the Marriott family.

Friends and family described her as an outgoing and beautiful girl, 'who was at prime of her life, but taken away.'