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Manual Interpretation Was Largely Inconclusive. TrueAllele® Connected a Serial Rapist Across Three Sexual Assault Crime Scenes.

Case summary

Human manual interpretation of the low-level 3- and 4-person mixtures was largely inconclusive. On the same lab DNA data, TrueAllele calculated match statistics from 33 mixture items. Eight of these items linked Johnson to the three sexual assaults. A jury convicted Johnson on 24 charges which carried a sentence of life without parole, plus 423 years to life.

What the lab report said

  • The case involved low-level 3- and 4-person mixtures, and human review of the DNA data was largely inconclusive.

Why this mattered for the investigation

  • This case had multiple crime scenes, multiple evidence items, and low-level mixtures that were difficult to interpret using manual methods. Without computer DNA interpretation, linking the suspect to all three crime scenes would have been challenging.

What was submitted

  • The lab’s electronic DNA data from 37 evidence items across three crime scenes (phone, clothing, a bathtub handle, zip tie, etc.)

What changed after TrueAllele interpretation

  • TrueAllele calculated inclusionary match statistics from eight items linking Johnson to the three sexual assaults.

Outcome

  • Johnson was found guilty on 24 charges and sentenced to life without parole, plus 423 years to life.

Case Takeaways

If your sexual assault case has multiple scenes, low-level mixtures, or mixed contact evidence:

  1. Request the electronic DNA data files (.fsa or .hid) for the probative items from each crime scene and reference profiles, including allelic ladder files.
  2. Request a Free TrueAllele Screening.
  3. If screening results are helpful, request a court-ready case report.

For more information on what to request from the lab, see the Sending Cases for TrueAllele Processing page.

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We don’t retest physical evidence items. We interpret the electronic DNA data a lab already generated.