CSI Guy

Single action revolvers have safety mechanisms built into them such as transfer bars and half-cock safeties. The firearm was found to be operable. This particular model has a firing on in the hammer, so there was no transfer bar. When the hammer is drawn back halfway or more, it cannot drop past halfway without the trigger being depressed. Aside from obvious issues such as what was a live cartridge doing in the chamber, any claims that Baldwin did not depress the trigger are false.

I presented this at the 2021 AAFS virtual conference. It relates to work that I performed on the Walter Scott shooting where I analyzed Michael Slager's uniform for potential damage from a cycling Taser. youtu.be/t4di1f8yFBE

Using long exposure photography to capture a laser representing an approximate bullet path gives clarity to your reconstruction, providing a spatial relationship between the bullet path and the scene context. It can be used to determine a reasonable range within which the shooter was standing.

When a bullet strikes a surface such as painted sheet metal, the resultant mark on the surface gives indications of directionality. Can you namy any?

@hwinkler4real It became a term in "the business": "You jumped the shark with this one" :-) Thanks for the great memories from my childhood. Aaaaaayyyyyyy. :-)

Me

@MattFinnFNC Hair evidence is transitory. Nancy (or someone else with legitimate access) could pick up a hair on her clothing/footwear anywhere and shed it in her home. If the hair had root material it could be argued it broke from it's source during a struggle.

FBI source on the Guthrie hair: •Its not new. It was recovered during the initial search. •FBI is getting it now after Pima County had it. (You may recall the controversy when Pima County sent evidence to its contracted lab instead of directly to the FBI.) •FBI using "new tech" to "untangle" DNA from the hair

@MattFinnFNC They won't be performing microscopic analysis after this scandal FBI Testimony on Microscopic Hair Analysis Contained Errors in at Least 90 Percent of Cases in Ongoing Review — FBI share.google/srHoihTQuDOJIZ…

The FBI won't be doing microscopic analysis of the hair after this scandal found 90% of testimony on hair analysis contained flawed statements. FBI Testimony on Microscopic Hair Analysis Contained Errors in at Least 90 Percent of Cases in Ongoing Review — FBI share.google/srHoihTQuDOJIZ… MtDNA will be their role. Remember, hairs are transitory, meaning Nancy could have picked up the hair on her clothing in another location and then she'd it in her home.

@Miss__Deana__ Great theories! I have a video about this in my timeline. It has to do with proximity to the expansion medium (ballistic gelatin). When there's distance between the Intermediary target and the gelatin, the material vacates the bullet's cavity. Very useful in reconstruction

@CSI_Experts_Inc 🤔 is it the age or temperature of the luan material that makes a difference?

Both top and bottom images are of JHP bullets that passed through 1/4 in luan material. Why did only the top set expand?

@RoseWorthesee @BrianEntin Nobody is saying that they can't. When no root material is present, only a mitochondrial profile can be developed. It's less precise and difficult to search MtDNA. Everyone in the same maternal chain has the same MtDNA

@CSI_Experts_Inc @BrianEntin This is not true. They can now extract a DNA sample from a rootless hair shaft. The Florida lab specialise in this.

The hair sample from Nancy Guthrie's house could be significant and comes at a time when scientists are able to get DNA off of rootless hair. This was not possible until recently. The technology is advancing quickly. More here: youtube.com/watch?v=VqNVJJ…

@StarowNiklas In NY OCME Forensic Biology uses MtDNA because there's still ~ 10000 charred remains from 9/11 so they're the best. With Rex Heuermann case, that's a matter of finding an unk sample and matching it to either a victim or a suspect vs trying to find an unknown person.

@CSI_Experts_Inc I refer to the Rex Heuermann case, where the NY lab claims to have extracted a fuller profile through the hair samples. I have no idea how it actually works, just that a lab claims to have done it.

"Rootless" hair can only produce a mitochondrial DNA profile. All the vial swabs/ reference samples already collected are analyzed for a nuclear DNA profile. Good for 1 to 1 comparisons, but as far as database searches.... good luck. Missing persons databases often have MtDNA profiles from degraded, unidentified remains.

Firearms analysis report on ballistic evidence in @charliekirk11 homicide. NOTE: This is about forensics and not politics The fired cartridge case matches the rifle that was recovered with suspect's DNA present. The "inconclusive" result for the bullet jacket fragment is not uncommon when analyzing fired bullets/fragments because fragments contain limited information, and bullets sustain significant damage when fired and impact intermediate/terminal targets. Fired cartridge cases usually do not. Lead bullet cores do not typically acquire characteristics from a barrel's rifling because those characteristics are captured by the bullet's jacket, not the lead core. Those are the markings that can individualize a bullet and match it to a barrel from which it was fired. Therefore, the lead fragments recovered are not likely to possess individual characteristics. Class characteristics of the land & grove impressions do not exclude the recovered rifle, however many different makes possess similar class characteristics. Cumulative weight of the fragments can be analyzed as a class characteristic that can exclude or include the fired bullet fragments as being consistent with bullets from the remaining live cartridges.

ESU are the unsung heroes of NYPD crime scenes. You guys sweep the locations for any perps who may still be hiding, conduct high quality searches when we have vast scenes, provide support with lighting, render uncommon firearms safe.... the list goes on. Thanks for your years of service for when a cop needs a cop. @emantk7

Backspatter from a porcine head. Understand that there's very little blood left in this head, so what comes back towards the shooter is tissue, bone and brain matter. youtu.be/kYo57x9ysgs?si…

I had made a series of videos picking apart the TV CSI shows. This was a funny one, worth some useful info. Travel back to 2012: youtu.be/Ahdsyi99iH8?si…