Ballistics experts can’t testify that recovered bullets matc

[jdege]

https://thedailyrecord.com/2023/06/21/ballistics-experts-cant-testify-that-recovered-bullets-match-firearms-md-high-court-rules/
Ballistics experts can’t testify that recovered bullets match firearms, Md. high court rules

The field of firearms identification is not reliable enough to allow expert testimony linking crime scene bullets to specific guns, Maryland’s top court ruled this week.

Using a new, stricter admissibility standard for scientific testimony, a split Maryland Supreme Court concluded that ballistics experts can only say whether the markings on a bullet are “consistent” or “inconsistent” with bullets fired from a particular gun.

“We do not question that firearms identification is generally reliable, and can be helpful to a jury, in identifying whether patterns and markings on ‘unknown’ bullets or cartridges are consistent or inconsistent with those on bullets or cartridges known to have been fired from a particular firearm,” Chief Justice Matthew Fader wrote in a 59-page majority opinion.

That a bullet could not have been fired from a particular gun seems easy enough to establish. If the striations don't match.

But if the striations do match a certain firearm, how certain can you be that there is no other firearm that would also match?

[Rip Van Winkle]

With modern machining techniques and mass produced barrels, I don't see how you could, with any level of certainty, identify a particular firearm from any other of the same brand and model. Especially after the bullet hits something solid.

[jdege]

With modern machining techniques and mass produced barrels, I don't see how you could, with any level of certainty, identify a particular firearm from any other of the same brand and model. Especially after the bullet hits something solid.

There was a time when the courts accepted isotopic analysis as evidence.

The theory was that any lead ingot would have a unique isotope ratio that could be used to determine which specific lot any given bullet came from.

The equipment had become good enough to measure such ratios to a great degree of precision.

What they didn't realize, until a defense team actually tested it, was that isotope ratios were not consisten across an ingot. They varied as gravity separated out isotopes of varying weights. And that the range within any given ingot exceeded the purported difference between ingots.

Because the researchers weren't asking the right questions.

[hard h2o]

https://thedailyrecord.com/2023/06/21/ballistics-experts-cant-testify-that-recovered-bullets-match-firearms-md-high-court-rules/
Ballistics experts can’t testify that recovered bullets match firearms, Md. high court rules

The field of firearms identification is not reliable enough to allow expert testimony linking crime scene bullets to specific guns, Maryland’s top court ruled this week.

Using a new, stricter admissibility standard for scientific testimony, a split Maryland Supreme Court concluded that ballistics experts can only say whether the markings on a bullet are “consistent” or “inconsistent” with bullets fired from a particular gun.

“We do not question that firearms identification is generally reliable, and can be helpful to a jury, in identifying whether patterns and markings on ‘unknown’ bullets or cartridges are consistent or inconsistent with those on bullets or cartridges known to have been fired from a particular firearm,” Chief Justice Matthew Fader wrote in a 59-page majority opinion.

That a bullet could not have been fired from a particular gun seems easy enough to establish. If the striations don't match.

But if the striations do match a certain firearm, how certain can you be that there is no other firearm that would also match?

You cannot say that absolutely that no two fingerprints are alike. You can not say absolutely that no two DNA samples are alike.

You can estimate what the odds are that a fingerprint belongs to a suspect or DNA belongs to a suspect. Then with other evidence you can conclude the certainty that a suspect is guilty.

[jdege]

Nearly everyone fails to understand basic statistics.

There was a case in LA, once, where witnesses had seen a black male and a blonde female in a red VW convertible commit some crime.

Shortly thereafter the police picked up a black male and a blonde female in a red VW convertible.

They were arrested, charged, and tried.

The case against them was entirely statistical. X% of the population are black males, Y% are blonde females, Z% of cars are red VW convertibles, the odds of encountering a black male and a blonde female in a red VW convertible is one in two million.

As is usual, asking the wrong question. The right question isn't what are the odds that a random couple in LA fits the description, but what are the odds that some couple in LA fits the description. With 4 million people in LA, how many times will one in two million occur?

Or, more precisely, given that there is one couple that fits the description, what are the odds that there's at least one more?

And for that, the odds were about 65%.

You have to ask the right question.

[Holland&Holland]

Nearly everyone fails to understand basic statistics.

There was a case in LA, once, where witnesses had seen a black male and a blonde female in a red VW convertible commit some crime.

Shortly thereafter the police picked up a black male and a blonde female in a red VW convertible.

They were arrested, charged, and tried.

The case against them was entirely statistical. X% of the population are black males, Y% are blonde females, Z% of cars are red VW convertibles, the odds of encountering a black male and a blonde female in a red VW convertible is one in two million.

As is usual, asking the wrong question. The right question isn't what are the odds that a random couple in LA fits the description, but what are the odds that some couple in LA fits the description. With 4 million people in LA, how many times will one in two million occur?

Or, more precisely, given that there is one couple that fits the description, what are the odds that there's at least one more?

And for that, the odds were about 65%.

You have to ask the right question.

They needed a short Italian with a hot girlfriend to defend them

[Lumpy]

The Spencer Tracy movie "Fury" is about a man wrongly suspected in a child abduction. He can't produce an alibi because he was with his two brothers and his fiancée, and the police are looking for "three men and a woman", which would drag them into it.

[Holland&Holland]

The Spencer Tracy movie "Fury" is about a man wrongly suspected in a child abduction. He can't produce an alibi because he was with his two brothers and his fiancée, and the police are looking for "three men and a woman", which would drag them into it.

Please, I will see your Sylvia Sydney and raise you a Marisa Tomei.

[ttousi]

With modern machining techniques and mass produced barrels, I don't see how you could, with any level of certainty, identify a particular firearm from any other of the same brand and model. Especially after the bullet hits something solid.

Years back I did research for a capital case. Based on the spent bullets recovered from the body and auto the following was all that could be established:
The bullets came from the 38 caliber family (380, 9mm, 38, 357)
The firearm barrel had a # 6 right twist
The bullets could have been fired from over 800 different firearms.

Basically the prosecution and defense came to the above conclusions based on bullet weight/deformity etc.

FYI..... I never did testify as a plea bargain was reached based on other facts that came to light.

So yes pretty tough to pin it conclusively to one firearm