<P> The killer then abducts a New York University student, who is taken to a derelict slaughterhouse, where he is tied to a pole . Part of his thigh bone is surgically removed, and he is left for rats to feed on . Amelia and Rhyme, using the clues left by the killer at the scene of Lindsay Rubin's death, find the victim dead . Again, the killer has removed a piece of the victim's bone . Amelia is able to collect the evidence, including another scrap of paper . The pressure of the tense investigation and bureaucratic challenges to Amelia and Rhyme's involvement with the case are having serious impacts on Rhyme's health and stability . </P> <P> After piecing together the message the killer was sending using the scraps of paper, Amelia and Rhyme are led to an old crime novel, whose crimes the killer was replicating . This leads them to his next victims, a grandfather and granddaughter tied to a pier as the tide rises . The girl is the first victim they manage to save, but her grandfather dies . At the scene, Amelia finds another bone, part of an old police badge, and an old subway map . These clues, and some asbestos left by the killer at the scene of Mrs. Rubin's death, lead Amelia to an abandoned subway station, where she sees some numbers which have been tampered with to spell out Rhyme's police badge number--Amelia realizes that the killer is after Rhyme . </P> <P> The killer arrives at Rhyme's house, and after killing Rhyme's nurse, Thelma, and Captain Howard Cheney, he is revealed to be the medical technician who cares for Rhyme's medical equipment, Richard Thompson . Richard's real name is Marcus Andrews, and he is a former forensics expert who worked in Syracuse . </P> <P> About 8 years ago, Rhyme wrote an article accusing Marcus of planting evidence and sending six innocent people to prison, and one of those people hanged himself . Marcus spent six years in prison, and after getting released, he spent two years trying to find Rhyme . Marcus was often attacked or raped in the prison, and he wants Rhyme to pay for what the article put him through . </P>

Who is the murderer in the bone collector