Cold Cases and the M-Vac – Guest Blog

Re-Blogged from Defrosting Cold Cases 26 Feb 2018

Guest blogging is always full of pressure, but writing for Alice’s Defrosting Cold Cases takes it to a whole new level. Like all of you, I thoroughly enjoy reading her posts and especially the Case of the Month that seems to hit my inbox at exactly 12:01 am on the 1st day of every month. Detailed, thoroughly analyzed, and full of insightful suggestions for the investigators. Every time I read one of her posts I hope the detectives responsible for the case she is highlighting will read it and take advantage of the path she has laid out for them.

So when Alice contacted me a couple of weeks ago to write this and give an update on what’s been going on with the M-Vac I knew I had to put some thought into it. Her readers, aka YOU, are much too experienced and sophisticated to be captivated by something that is just thrown together. What have I come up with? Read on!

Let’s start with what this blog is all about – cold cases. Since my last guest blog the M-Vac has done some amazing work. How about collecting touch/trace DNA from a 39 yr. old halter top that was used as a gag? Last summer Patrick McCabe was convicted and sentenced for assaulting, raping and murdering Sharon Schollmeyers in 1977. She was an innocent teenager who lived in the apartment complex he managed. Using his manager’s key, he broke into her apartment, tied her up and gagged her with her own clothing, raped and strangled her to death, then placed her body in the bathtub. As a convicted child sex offender his DNA profile was in the CODIS database, so when the profile from Schollmeyers’ murder was uploaded the connection was made and McCabe was arrested in Florida. He later confessed to the killing to avoid the death penalty. This case received some local coverage, but didn’t reach national attention until Forensic Magazine highlighted it last June.

In the last year the M-Vac has also been shown to work well with rapid DNA systems. In a large North Carolina sheriff’s department, the M-Vac successfully collected DNA from a pants pocket, a pair of boots and a wallet, all from a cold case homicide that was over a decade old. The DNA profiles were independently produced using the RapidHT system. The state lab had processed cuttings and swabbings from the case, but with an obvious lack of actionable results. This case is ongoing, hence the absence of location and case details, but the exciting takeaway is using the M-Vac with a rapid DNA system can produce effective results, and in 90 minutes. Rapid DNA technology and the potential to solve crimes in hours and not weeks, months or years is approaching the Gattaca space age level, but the technology is not yet as sensitive as an actual crime lab process. Therefore, using the M-Vac to collect more DNA material is an effective way to counteract that.

The last case I want to discuss is the Carrie Singer case. You may already be familiar with this case as it is also the Isle of Wight Sheriff’s Office case that is the focal point of the Discovery Channel’s The Killing Fields. If you haven’t seen the show, even as an investigator it should be entertaining and interesting enough that it’s worth the time to watch! Carrie Singer was a 28-year-old mother who was found murdered in a remote field in Isle of Wight County, Virginia, in 2004. She was still wearing a sports bra and shirt, but was missing her pants and underwear. Using the M-Vac, investigators were able to get a foreign male DNA profile from the sports bra, which didn’t match a nipple swab that was taken from the victim at the scene. It did match, however, a dirty rag that was found underneath her. Not only was the DNA material collected sufficient to produce a profile, it was also enough to use Parabon’s Snapshot software to generate a likely image of the suspect, and identify the likely race. This has significantly redirected the investigation toward a completely different suspect pool. We’ll find out on February 22nd if they are able to positively identify the suspect. You should tune in!

Clearly we could go on and on. Helping solve cold cases is an exhilarating experience, so I am beginning to understand why Alice has been such an advocate for so long. Next month the Discovery Channel is launching a new TV program, and the first episode (March 5th) will be on the Krystal Beslanowitch murder from 1996. In that case the M-Vac collected DNA from a couple of granite rocks, helping solve the case 18 years after the victim was found. A&E is also airing a new crime program, and in an episode the host will talk to a DNA expert about how the M-Vac might be used in the Chandra Levy homicide. Why bring up these cases and media programs? Because now crime shows are all the rave, and they are obsessed with new technologies that investigators and agencies are using to solve crimes.  Same trend is happening with the news. Solving crimes, and especially cold cases, is becoming big business for media companies and news agencies, and that in turn brings an amazing amount of attention to the cases that are still unsolved. Hopefully that will also mean more resources! Here’s a link to a news clip that shows exactly what I’m talking about.

When we are describing wet-vacuum forensic DNA collection at demos or at a conference, pretty much every investigator can think of a half-dozen or more cases where they want to use it. The M-Vac may not be appropriate for every case, but if swabbing or another traditional method has failed then why not give the M-Vac a shot? Based on the feedback we get from agencies that are using it, there is a 40-50% success rate on evidence that is resubmitted and the M-Vac is used, and even higher if the previous result was a partial or inconclusive. The bottom line is this is a tool that every investigator needs access to. Now that the word is getting out both through the law enforcement agencies sharing case studies, news media, TV shows and awesome blogs like Defrosting Cold Cases, “M-Vac-ing” is becoming a common vernacular in the crime solving world! If you have an M-Vac story, please share it with us!


Jared Bradley

Jared Bradley

Jared Bradley is President and CEO of M-Vac Systems, Inc. He has an extensive background in leadership, sciences, operations, and marketing. He has worked for M-Vac Systems for almost 12 years, including 9 years as the President. Prior to M-Vac Systems he worked in sales and sales management for both small and international corporations such as Pfizer. He served 14 years with the US Army and Army Reserves, achieving the rank of Captain.

Since leading M-Vac Systems into the forensic market Mr. Bradley has had the opportunity to teach people all over the world about the M-Vac and wet-vacuum DNA collection including UK, Germany, France, Canada, South Africa, UAE, Oman, China, Australia, Thailand, Vietnam and all over the United States. Mr. Bradley has a BS from BYU and an MBA from Strayer University.

He enjoys the outdoors, especially camping and hiking the Utah Mountains with his wife and five children.


King’s College in London Finds M-Vac Collects 75% More DNA From Bricks Than Double Swab


  • The M-Vac® was superior to double swabbing for DNA collection from brick surfaces.
  • Double swabbing collected more DNA than the M-Vac® on non-porous tiles.
  • Cell-free DNA is lost in the filtration step of M-Vac® processing.
  • The M-Vac® is a useful option for DNA collection when traditional methods fail.


Collecting sufficient template DNA from a crime scene sample is often challenging, especially with low quantity samples such as touch DNA (tDNA). Traditional DNA collection methods such as double swabbing have limitations, in particular when used on certain substrates which can be found at crime scenes, thus a better collection method is advantageous. Here, the effectiveness of the M-Vac® Wet-Vacuum System is evaluated as a method for DNA recovery on tiles and bricks. It was found that the M-Vac® recovered 75% more DNA than double swabbing on bricks. However, double swabbing collected significantly more DNA than the M-Vac® on tiles. Additionally, it was found that cell-free DNA is lost in the filtration step of M-Vac® collection. In terms of peak height and number of true alleles detected, no significant difference was found between the DNA profiles obtained through M-Vac® collection versus double swabbing of tDNA depositions from 12 volunteers on bricks. The results demonstrate that the M-Vac® has potential for DNA collection from porous surfaces such as bricks, but that alterations to the filter apparatus would be beneficial to increase the amount of genetic material collected for subsequent DNA profiling. These results are anticipated to be a starting point to validate the M-Vac® as a DNA collection device, providing an alternative method when DNA is present on a difficult substrate, or if traditional DNA collection methods have failed.

NOTE FROM M-VAC SYSTEMS:  Although we have not obtained the raw data, methods used etc, we find these results very exciting as well as expected.  Clearly the data is significant enough for the police in the UK and around the world to recognize how much they need this new forensic DNA collection capability.  The fact that the double swab collected more DNA from the non-porous tiles is not surprising nor a revelation, especially if the DNA material was concentrated in a relatively small area.  We rarely recommend using the M-Vac over the swab in that scenario.  Also, cell-free DNA is far too small to be captured on the filter we commonly use (.45 and .20 micron PES filters) so that is not a surprise either.  Most of the time the M-Vac collects enough cellular DNA that the free DNA is insignificant anyway and does not affect the quality of the DNA profile.  The bottom line is the M-Vac has now been successfully tested by research universities in the US, the UK, Sweden, and more testing is going on in Australia and elsewhere by police agencies, crime labs and research facilities.  And, once again, the M-Vac system has shown it is a valuable tool for generating DNA profiles where the other collection methods cannot!

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