Why M-Vac

DNA Labs Int M-Vac Case Studies 2017

M-VAC SUPERIOR DNA COLLECTION TECHNIQUE

DNA Labs International has years of experience from working nearly 100 cases processing evidence with the M-Vac® for DNA testing. M-Vac Systems®, Inc, is helping solve more crimes by collecting more DNA than ever before. The M-Vac® utilizes the same principles as a wet vacuum. It raises the sampling standard, and we have proven it can dramatically improve DNA collection.

Why M-Vac®

  • Advancements in DNA technology have led to a higher volume of touch DNA samples being submitted to forensic laboratories.
  • Touch DNA refers to samples where biological fluids are not detected, but skin cells may be left behind due to contact.
  • Traditional collection methods, such as swabbing an item, are not always sufficient to collect the small amounts of DNA left behind.
  • The M-Vac® system was validated by DLI in 2014 to improve recovery from touch DNA samples.

How It Works

  • Using the sampling head, a sterile buffer is sprayed onto the surface of the item.
  • The buffer is re-collected by applying a vacuum pressure over the sprayed area.
  • The buffer now contains suspended particles including DNA from the item.
  • The buffer is poured through a sterile filter under vacuum pressure which causes the DNA to bind to the filter and become concentrated.
  • After allowing the filter to dry, it can be sampled and extracted.

CASE STUDIES

CASE 1 – END OF THE ROPE • A robbery occurred where the criminals used a rope to enter through the roof of the store. • The rope was left behind at the scene. • During screening, the rope was tightly coiled together and the M-Vac® was used to sample the entire surface of the rope. RESULTS • The DNA profile indicated a mixture of at least four individuals contributing to a major male and a minor DNA profile. • The major male DNA profile is suitable for comparison. • Probabilistic genotyping – STRmix - may be used for the minor DNA profile.

CASE 2 – HOT ROD • The police responded to a vehicle fire in the Police Station parking lot. • They witnessed a man attempting to set several cars on fire by placing a bed sheet underneath them and igniting it. • The bed sheet was left behind at the scene and collected as evidence. • During screening, the M-Vac® was used to sample both sides of the entire sheet. RESULTS • The DNA profile indicated one male contributor and matched the DNA profile of the suspect.

CASE 3– BATHROOM BRAWL • Victim's body was located in the bathroom at his workplace in 1992 after an apparent struggle. • It appeared as though he locked himself in the bathroom and tried to exit via the ceiling to escape from his attacker. • Based on evidence found at the scene, the victim may have been pulled down from the ceiling by his attacker. • The M-Vac® was used to sample the victim's pants avoiding any bloodstains. RESULTS • A foreign male DNA profile was able to be deduced assuming the victim is one of the contributors and was uploaded into CODIS.

CASE 4 – HOTEL HELL • Victim was found inside his hotel room beaten to death in 1987. • He was bound to the bed and his jean pockets had been turned inside out. • In 2011, the pockets of the jeans were sampled using the traditional swabbing method and very limited data was obtained. • In 2016, the pockets of the jeans were re-sampled using the M-Vac®. RESULTS • A minor DNA profile foreign to the victim was obtained from the pockets and was uploaded to CODIS

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References:

DNA Labs International has owned an M-Vac System for years and by early 2017 has processed almost a hundred cases with their system, seeing numerous successes. Needless to say DNA Labs International is one of the M-Vacs most ardent supporters as they have been instrumental in helping solve a number of extremely difficult cases, as can be seen above. They have also produced articles and white papers not only showing their superior understanding of the wet-vacuum concept but also the importance of it in helping solve more crime. Keep up the great work DNA Labs!  

DNA Labs International is a ISO/IEC 17025:2005 and FBI QAS DNA Laboratory ®

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