Police have arrested a man for the seemingly unprovoked stabbing death of a young woman in a Massachusetts public library.

Police say 23-year-old Winchester, Massachusetts, resident Jeffrey Yao abruptly walked up behind a woman sitting in a Winchester library and stabbed her repeatedly in the neck, back and head with a 10-inch knife, the Associated Press reported.

Middlesex District Attorney Marian Ryan said the grievously wounded woman tried to head for the exit before collapsing. A 77-year-old man who tried to aide the fallen woman was also slightly injured by the assailant, Ryan said.

Neighbors of suspect Jeffrey Yao say they saw warning signs of bad behavior in the past & reported him to police for vandalism. Now he’s charged with murder for stabbing a woman to death inside a public library today. Details at 10PM @boston25 pic.twitter.com/NA1EQQaRgj — Litsa Pappas (@LitsaPappas) February 25, 2018

The victim was home from college and was studying at the library, friends told authorities.

According to Fox News, police have been warned about Yao in the past. Ryan noted that Yao was “known to police.” In addition, the suspect’s Facebook page is filled with pro-Palestine, anti-Semitic, and anti-Trump posts.

Police had no motive and were unsure if the suspect knew the victim.

Yao has been charged with murder and armed assault with intent to murder and is being held without bond.

Follow Warner Todd Huston on Twitter @warnerthuston.