Crime lab/Investigate skill...Not Elementary my Dear Watson

[broghammerj]

I was reviewing the skill set for d20 modern and have been left with a question regaurding a crime lab and it's use with the investigate skill. Investigate has two uses: analyze clue and collect evidence.

Analyze clue is relatively simple....The bullet hole is here, the shooter must have been over there. Or skin under the finger nails makes it look like there must have been a struggle.

Collect evidence is much less straight forward. On the surface it's relatively easy. There is a proper way to get DNA samples, cast a tire track, dust for prints, etc. Can your character do these things? Depending on how well you collected evidence, you may have earned the crime lab a bonus or penalty on analyzing evidence. Are you the one who screwed up the OJ Simpson DNA sample????

My question is are there stats anywhere for a crime lab? I can't seem to find anything in the book. My assumption is that the lab's investigate:analyze clue skill rank would higher than the characters. This would motivate the character to collect evidence properly by using their investigate: collect evidence, otherwise they would just analyze clue themselves.

Are some DMs simply using the crime lab as a story tool? The characters use the investigate skill to collect evidence and the crime lab simply matches the ballistics of the bullet or matches the perp's DNA to the crime scene without any roles. The DM just uses the lab to advance the story.

Thanks for the help.

 

[BrooklynKnight]

A Crime Lab would have Mastercraft equipment that allowed for the proper analyzing of clues and would be staffed with individuals with high ranks in that skill, typically higher then that of the normal populace.

Some CrimeLabs would give those working there anywhere from a +2 to a +8 bonus.

Take for example the NYC Crimelab. It is staffed by Melinda Carpenter (Smart 10), she's devoted her life to sciences. She has full ranks in investigate (13) a 17 int (+3) and works at a crime lab that offers her a +8 bonus. Thats a +24 to her roll. I think you can take 10 on the check, and typically they dont analyze in a rush, so that gives an average result of 34 on the check.

You can see why a PC would want to use an actual lab. Unless they have the resources to obtain the proper equipment, and the time to focus on the analyzation themselves, its better to pay to have it done.

 

[Turanil]

I think you will have to make a houserule here.

In D&D having an alchemical lab is required to manufacture alchemical products, and provides a +2 bonus to the Alchemy skill check. A very simple way would be to do things like that. Now to make something more realist, it would probably require to have someone who knows of that kind of work to bring some coherent houserule.

 

[BrooklynKnight]

Such as myself :-D

 

[2WS-Steve]

Page 213 in the d20 Modern book has some sample skill bonuses for crime labs. That little section over those couple pages has a few nice bits for GM's--too bad it's somewhat hidden.

 

[broghammerj]

Page 213 in the d20 Modern book has some sample skill bonuses for crime labs. That little section over those couple pages has a few nice bits for GM's--too bad it's somewhat hidden.

This was exactly what I was looking for. I'm restarting a game and haven't played Modern in a while. My rules review didn't turn up that chart. Now I'll throw something else at you. What are the DC checks for the following items:

1. Match DNA samples from relatively good samples/bad samples.
2. Match tire tracks to a make and model of vehicle.
3. Match finger prints from a perp to a crime database.
4. Match a bullet to the gun it was fired from.
5. ID a body based on dental records.
6. Determine age/sex of a person from a pile of bones.
7. Figure time of death based on body temp, insect infestation of the body, etc.

I'm running a CSI type game. Thanks everyone for the ideas so far

 

[Turanil]

Such as myself :-D

Actually, when I did read the question, you still hadn't post your own answer. See the time: 6-45 and 6-50. Well, I am not so dumb after all!

 

[HeapThaumaturgist]

1. Match DNA samples from relatively good samples/bad samples.
2. Match tire tracks to a make and model of vehicle.
3. Match finger prints from a perp to a crime database.
4. Match a bullet to the gun it was fired from.
5. ID a body based on dental records.
6. Determine age/sex of a person from a pile of bones.
7. Figure time of death based on body temp, insect infestation of the body, etc.

EDIT: After thinking on this for a moment, another idea I've had is to incorporate a "Skill Results Ranges" for each item. Sort of like Alternity. If you have quite a few "ways" to look at evidence you can assign each of them different DCs and either roll multiple Investigate checks or reveal certain details depending on the final roll. Say you have "A Blood Spatter" the data you could get from that may be broken down like this.

Investigate, "The Matheson House Blood Spatter"

• DC 15 - The blood type is AB
• DC 17 - (requires 12 hour analysis) DNA matches Mrs. Matheson
• DC 20 - Blood spattering suggests Mrs. Matheson at kneeling or sitting level at time of attack
• DC 25 - Secondary cast-off suggests long, blunt instrument (possibly a bat, club, or tire iron)

The PC rolls his Investigate to work on the blood spatter. He nets a result of 22, so he gets the first three results from the table up there. Hopefully the bloody bat in the basement will tell them what they missed from the secondary cast-off splatters.

As to the original post ...

These are ranges based on/extrapolated from the data in the Investigate skill and applying it, as a DM, to these instances. It's sort of open to interpretation and, like any skill in d20, begins to break down once base skill levels reach < +17-18 (I.E., when rolling is less important than the base skill.)

1. Match DNA samples from relatively good samples/bad samples.

Good sample: DC 15, DC 20 outdoors. I would imagine more like 17-20, based on blood evidence being predominantly indoors, yet often discovered 1+ days after the crime (+2 DC per day).

Bad Sampe: This would be a botch on the collection, so the investigator would either take a -5 on his roll, or the DC would be raised by 5. So, here, I'd say the range would be DC 20-25.

2. Match tire tracks to a make and model of vehicle.

DC 20-25.

Unless somebody is driving through the house, you're starting with a +5 outdoor penalty.
I'd say this one is pretty easy. If you want to make this more interesting, I'd allow a +2 Synergy Bonus for 5+ ranks in Research (going through all those models of cars).

3. Match finger prints from a perp to a crime database.

DC 15-20

DC 15 and, again, I'd allow a +2 synergy bonus for Research, for using the databases. Remember to apply all of the circumstance modifiers ... +5 outdoors (DC 20) ... clumsy cop collected it? +5 (DC 25). Etc. Etc.

4. Match a bullet to the gun it was fired from.

See #3.

5. ID a body based on dental records.

DC 20-35

And again, same thing. I'd say with a body so bad only dentals there'd be a high DC. Start at 15. Outside? 20. Fire? I'd say that's "Scene Very Disturbed" so +6. DC 26. Body outside for several weeks? +10 DC 36.

The DCs can rack up pretty quickly, if you think about it. On average, I'd say

6. Determine age/sex of a person from a pile of bones.

DC 25+

This is really alot like the one above. It's bones. I'd say +10 DC right off the bat for time passage. We're starting at DC 25 from there. These situations, with deteriorated scenes and old crimes, are where expert collection comes into play. Somebody with a +10 Investigate collecting

7. Figure time of death based on body temp, insect infestation of the body,

DC 15-17
DC 25-36

Time of death on body temp? Easy, DC 15-17. Having a corpse with a body temperature means it's probably within 24 hours or so.

Basing on insect infestation? Harder, that means months have passed. Probably at least DC 25, then DC 30 if outdoors ... DC 32-36 if the scene was obscured or disturbed in some way.

Those are my takes on it. Since it's a big part of your game, I'd collect all of the data (including the chart) in the Investigate description into a table or two that you can keep on hand or on file. The DCs can vary widely, as you see, and with difficult/old specimines it'll be important to have a PC collecting the evidence to analyze. (Getting rolls of 20,25,30+ to add bonuses to the analysis rolls).

--fje

 

[jaerdaph]

As a related aside, Mongoose Publishing's OGL Horror added two new uses to this skill – Organize Search and Reconstruction (of a crime scene).

 

[takyris]

I use rules similar to what HeapThaumaturgist uses. The better you roll, the more you find out. An Investigate check of 15 will let you find out a bit, 17 a bit more, 19 a bit more than that, and so forth. Even my PCs with high ranks in Investigate will sometimes throw an action point in there, because they know I've made some terribly helpful clue that you only get if you beat DC30.

Question for broghammerj: are your PCs the ones in the lab, or are your PCs the ones doing the fieldwork -- or both? If they're the ones in the lab, then these are good numbers to get conclusive and consistent numbers for -- ie, "matching a bullet to a gun requires an Investigatigate check of DC15, with a possible +2 synergy bonus from ranks in Knowledge(Tactics) and/or Knowledge(Physics), as well as a possible +2 circumstance bonus from having Personal Firearm Proficiency. This is the base DC -- a damaged casing or deliberate alteration of the gun's muzzle can increase it."

If they're the field people, though, like my PCs are, I tend to use the lab as a kind of game-based 20-questions machine, if that makes sense. The evidence, if collected properly, will allow the techs to give my PCs yes or no answers to any question I think reasonable for the evidence collected. "Yes, this blood is different from the blood of the victims. Yes, it shares alleles, meaning that it's the blood of a family member. I'm sorry, we can't tell whether or not the gun you found is the murder weapon. It's definitely the same type of weapon, but unless you can get us more evidence, we can't confirm or refute that."

I wouldn't roll for what happened in the lab unless the PCs are there -- if I wanted the lab to screw up an evidence check, I'd just have it happen as part of the plot.

That's one of the things I'm liking more and more about d20 Modern -- the degree to which I can add in or take out die rolls as needed.