A 20-year-old student discovered her $80 textbook on sale at Student Book Store, 417 E. Grand River Ave., the same day it was stolen.The student reported the blue and white plastics textbook stolen Monday from the Main Library after she left it unattended at about 3:45 p.m. in the west basement area, said MSU police Sgt. Florene McGlothian-Taylor.Initially, the student thought she had lost the book, but when she went to the bookstore, she found only one used version of it.The student discovered her yellow, purple and pink highlighting in the book, McGlothian-Taylor said.She was able to prove the connection to the bookstore, which returned it to her for free.The case is still under investigation.A $100 Dell computer modem tower was stolen from an Abbot Hall computer lab sometime between Sunday night and Tuesday morning.A 44-year-old employee who discovered the tower was missing said the 24-hour computer lab is never locked.Maggie Lillis