| First Name | Marvin |
| Last Name | Mitchell |
| Year of Conviction | 1990 |
| Year of Exoneration | 1997 |
| State of Conviction | Massachusetts |
| Trial, Bench Trial, or Guilty Plea | Trial |
| Type of Crime | Rape |
| Death Sentence | No |
| Gender of Exoneree | Male |
| Race of exoneree | Black |
| Juvenile | No |
| Types of evidence at trial |
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| Type of Forensic Evidence |
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| Types of Flawed Forensics |
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| Reason why invalid | (1) Masking |
| Brief Quote / Description of Testimony | Stains exhibited blood groupings consistent with Type O, which was the victim’s type. However, Mitchell was an A secretor. The analyst testified, “Mr. Mitchell could not be excluded. No secretor could be excluded from depositing that stain because the stain may have been too diluted or graded to pick up Mr. Mitchell’s blood type. So I cannot exclude him, but I cannot say that I found the A blood group type.” While it was correct that Mitchell was not excluded, the analyst never explained that no donor could be excluded; the analyst stated that only secretors can not be excluded. See Part II.A.1 for a description of this case. |
| Identity of eyewitness |
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| Highest level reached | Appeal |
| Claims Raised During All Appeals and Postconviction |
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| Harmless Error Rulings |
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| Citations to judicial opinions | Com. v. Mitchell, 619 N.E.2d 619 (Mass. App. Ct. 1993) |