Some Italian lawmakers claim Amanda Knox was treated unfairly and are seeking a probe into the prosecutors' office in Perugia, where the American student was convicted of murdering her British roommate.

The request to the Italian justice minister Thursday is spearheaded by a lawmaker who has frequently visited Knox in prison and has written a positive book about her. The lawmaker also sent a letter to the Italian president seeking his intervention.

Both the petition and the letter cast doubt on the prosecution's case, alleging that an appeals trial currently under way has undermined the reliability of evidence originally collected against the former student from Seattle. They also maintain that Knox should not have been kept behind bars since her arrest.