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3 Person Mixture #3
The Hickey CaseConsensual or Suspect??
Scenario
• The event occurred in a hotel room closet where Victim went to pass out in peace
• There were a total of 5 people “socializing” that night
• But, she was pretty sure it was a guy that had sex with her in that hotel room closet
• A condom wrapper was found in the closet
Scenario
• Kit was negative for semen, condom used?• But, Victim had a hickey on her neck• Victim says she “messed around” with
another girl, but “nothing really happened”• She says she would “never make out with a
girl” but she was really drunk• Evidence is a swab of the hickey on V’s neck
The Egram
The Confusion
• I’m getting conflicting information from the investigator
• I can’t tell if the other girl will be considered a “consensual” partner or another suspect
• They refer to her various ways in the supporting documentation
• Case happened on the other side of the world, so it’s hard for me to call the Investigator
The Confusion
• The defense may argue the other girl was at least a consensual “make out” partner to advance their theory that Victim was “in the mood” and it was consensual
• Who knows? Perhaps Victim may claim assault against the other girl, making the other girl a suspect
• So I decide to hedge my bets and prepare to do it both ways
Start the Interpretation
• Start by hiding C? and S profiles• Apply Victim reference• Set to 3 people• Autocall references
– List foreign box– View call report
Start the Interpretation
• We’re going to discuss some things about some loci, then I’m going to do a whole bunch of clicking to get the profiles interpreted/deconvoluted
• Hopefully, I’ll explain it well enough during the discussion that you’ll follow it easily enough
• If not, someone yell at me and I’ll do so
Start the Interpretation
• Here’s where we start (1 option only at D8)
We learned:V is midlevel There is a MajorMale is minor ≈5% (We knew that due to small Y)
We could have eyeballed it
Don’t worry about these names, it’s just the default for 3 people
Interpret As Two Unknowns Present
• So here’s a novel idea based on:– Several loci with no minor visible alleles– Minor is <10% apparently– With “good” data like this, “typical” mixture
proportion variation falls into a 10% window– Minor is within the “margin of error”
• Forget about the minor and just worry about the Major Major and the minor Major (V)
• But we won’t switch to 3 person
Interpret As Two Unknowns Present
• At the following loci you can easily call the Major Major because the minor Major is the profile of the Victim (her own neck swab)
• In fact even though there are multiple options for contributor combinations, the center section is the same in every option
• (So you know what the Major type is)
Interpret As Two Unknowns Present
D21 (Example) D2 D3
THO1 D19D7 TPOX
No confusion about Major at these loci in calculator Most of these we can “eyeball” pretty well
Interpret As Two Unknowns Present
• Start at D21• V is 29, 30• The center section below will always be the major
Interpret As Two Unknowns Present
• Every center option requires 28, 30.2 for major• Also minor <10%
Interpret As Two Unknowns Present
D21 (Example) D2 D3
THO1 D19D7 TPOX
No confusion about Major at these loci in calculator Most of these we can “eyeball” pretty well
Interpret As Two Unknowns Present
• There are 3 loci with same type in all contributor options, but some are “not excluded” types so no P/PHR info (D18)
• But, there is a subtle pink highlighting to some types that means “RFUs below HT” - minor
So ignore pink
• 3 loci with common foreign type to all options• Is always the major, or at least no pink flag
Interpret As Two Unknowns Present
D18
D5
D16
Interpret As Two Unknowns Present• CSF requires shared types• Correct for stutter, and the 11,11
is the major type• Plus the “eye ball” method helps
• Three loci have quite a few options in calculator (we stayed in 3 person mode)
Interpret As Two Unknowns Present
FGA
D13
vWA
Interpret As Two Unknowns Present
• FGA - all options but the bottom one have a 21, 22 Major• But that option is kind of 1:1:1
Plus you can eyeball it and tell you have a 21, 22 but no clue about third minor person
Interpret As Two Unknowns Present
• vWA – Even though lots of options it’s really a no brainer knowing V is 16, 16
Major is 17, 18
Only the options for a 17, 18 have tiny minor for the 3rd person
Interpret As Two Unknowns Present
• D13 – V is 11, 13• Appears to be lots of options• But 13, 13 no good for a major • If 11, 11 major, then V proportion = 79% not 30ish
So V and Major are both 11, 13contributors
Interpret As Two Unknowns Present
• We’ve ended up with a full deconvoluted major profile
• If you assume the V, you may be able to “eyeball” and do it also
• But we used phr and p information to do it
Interpret As Two Unknowns Present
• Now we check to see if we have a match• Just for fun, let’s match backwards• We’ll set the deconvoluted major profile as
the reference and back check against the known samples
• (This works well in big cases with mulitple known references)
Interpret As Two Unknowns Present
• The deconvoluted profile is a perfect match against the C? sample
• (Our girl that may or may not be a consensual or a suspect)
Interpret As Two Unknowns Present
• Single source stat• 1 in 346 Sextillion • But check Hispanic – Septillion!
The Third Contributor
• We have a low level male contributor that we’ve ignored so far
• But we decided he was so low that he didn’t have any bearing on the other two contributors
• So treat it as a Type 0 Mixture– It’s just a partial profile– Probably a bunch of Allele, Any’s
The Egram
The Third Contributor
• 2 minor alleles at D8, so we know the type• D3 and D19 >300, but test for stutter
– Obligate function?– If I forget to check stutter for D3 and D19 when we
click it into the Questioned profile, remind me
• Use Allele, Any’s – In most 3 person “real life” mixtures I’ll probably default to Allele, Any for anything close to 300 as they’re much more unpredictable than a 2 person mixture near HT
The Third Contributor
• 4 loci with no minor alleles showing• D13 and vWA amp pretty well, so maybe no
drop out (D13 has only 2 alleles, can do 2 Anys)
• FGA doesn’t always amp well and is largest red locus
• CSF is very large locus
The Third Contributor
• Final stat (almost, vWA is 90% of population, not 100%)
• 1 in 85.3 Million (It should be 94.1 Million)
The Third Contributor
• Let’s check to see if suspect fits that minor
Final Thoughts
• This was actually really easy mixture, with an obvious major and obvious partial profile
• Those loci with no minor alleles called– LR would use those loci– Why can’t we use them in RMP?– It makes no sense not to– But remember, sometimes LR will favor defense at
loci where there is drop out (FGA)– RMP can’t do that, but becomes “Neutral”- 1.00
Final Thoughts
• But RMP is much more powerful than perhaps you realized
• Are you sure you need LR (with drop out?)• (It would be nice to have it though… Stand by)
• Oh yeah, and the program rounds to 1.0 for any RMP that adds up to >1.0