When Mary reads the case file after breaking into the police office, the word "HOMICIDE" is misspelled "HOMOCIDE".
The witness at the mini mart said a blue Malibu. Mary found a blue Malibu. When it showed the flashback of Tony and the victim the car was a Chevelle.
Mary is not wearing latex gloves in any of the crime investigation scenes so her fingerprints would be all over everything she touched.