An autopsy conducted Sunday on the body of 20-year-old University of Chicago student could not determine the actual cause of his death. The Cook County medical examiner said that the result of the toxicology tests is still pending.

The police officials found the body of the third-year student Nicholas Barnes in the dorm room Saturday afternoon after students complained of a foul odor in the hallway. "While I was going to my friend's room (Saturday) I like smell a foul smell," said student Eva Kenabrew, abc local reports.

The decomposed body of the student was discovered lying face down on the floor of his room at the school's International House Residence Hall in the 1400 block of East 59th Street.

The student appears to have been dead for quite some time because the last time he used his key card to enter the residence hall Feb 7. The University officials said that students need not use the card all the time to enter and exit the hall, indicating that Barnes could have accessed the building after Feb. 7 as well.

Residents were confused and surprised to learn that nobody seen or talked to Barnes or even noticed his disappearance.

"It's just strange," said Neal Jochmann, 19, a freshman from Tennessee. "How the hell was he there that long? That's frightening," Chicago Tribune reports.

"I don't understand how the people that live next door, and the people who were responsible for his well-being could have not seen that he has been gone for a week," said International House resident Jordan Ginsburg.

University officials claimed that his death was not the result of a suicide and there is no evidence of foul play.

 "Our thoughts are with Nicholas' family and friends ... and all who are touched by this loss. Nicholas was an excellent student, admired by faculty and peers alike," Karen Warren Coleman, vice president for campus life and student services, said in a statement.

Barnes from Pittsburgh was majoring in Germanic studies. He was also part of the school's literary publication, Sliced Bread.