Solo RPG Investigation Framework

#Solo RPG Crime Scene Investigation Framework

Edit: This is a work in progress. I will be adding more examples and defining the framework with further rules in this page. I will be making short blog posts about updates referencing this link when this happens.

Preface: These rules are to facilitate a solo rpg crime scene adventure.
It’s meant to run without a story framework or threads, since knowing what happened kinda ruins the surprise. I seriously urge the reader to follow the rules on Solo Metagaming and how to avoid it, as the entire concept is based on this.
I’ve tested these with a homebrew D6 system, but it’s supposed to be system agnostic.

Order of set up for crime scene

  1. First of all define the Known Information

    The crime scene was called in by someone. Who was it? When was it called in?
    Where is the scene?

  2. Then, define the Obvious Information

    What is visible at a first glance?
    Is there a missing body part? Is there a weapon on the floor?

  3. Ask the Investigation Information

    This requires an investigation skill roll. Depending on the outcome you get one or more questions to the Oracle, regarding non obvious items.
    Since most game systems are not mechanically based on delivering information to solo players, I suggest that you use the relevant skill, and decipher the result in a way that a moderate success will answer 3 Oracle questions.
    Are there bullet holes? Is there a wound that may be the cause of death? Are there signs of struggle?
    Example modifications:

    System Rule
    OpenD6 Every 5 points of success, is one answer
    Savage Worlds Success 1 answer, Each raise 2 answers
    D100 Systems Every 10 points of difference from skill, is one answer
  4. Run a specific Search Information

    This requires a successful search roll. You must define beforehand what you search for. It could be for example shell casings. If it’s probable that the item is hidden, then increase the difficulty.

  5. Finalize Follow up Information

    If any of the above could generate more questions that can be answered at the scene, go ahead and ask them. If there are bullet holes, ask how many. If a knife was found ask if it has blood on it. Don’t ask the about the bullet diameter or whose blood it was on the knife. These need a forensics lab.

  6. Run Field Examination Information

    If the investigator has a kit at hand to examine gunpowder residue or blood stains, then perform the respective skill rolls and ask the Oracle.
    Likewise if there is a witness, run the respective social skill and questions and ask the Oracle for the answers.

Notes on rules

Always ask the Oracle after any successful skill rolls. The fact that your investigator has a keen eye and rolled a critical success on the search roll to find shell casings doesn’t mean that there are any to be found. Though they can be certain that they would have found them if they were there. So maybe the gun was planted since it wasn’t a revolver… who knows?

Run a separate investigation roll for the crime scene and the location. Trying to find clues in the location of
the crime is quite different than defining if anyone in the neighborhood could have seen anything.

NPC or item generators are very useful, but one must be careful to use only the relevant information. If the generator states that the priest secretly worships an evil deity, disregard it, since there is no way your character would know. If it says that his hair is black, keep it.

The Oracle will take your story in its own direction. Embrace it and go with it. The more a story progresses, everything will either get clearer or blurred. Makes sense. Not all crime scenes are to be solved, even by the best investigators. Sometimes the bad guy has confused everyone so much, they get to walk away.
Also some clues won’t fit. Maybe they were irrelevant or their link is lost. Don’t fret over them, try an approach from a different angle.

These are system agnostic and Oracle agnostic rules. If your system has a separate skill for interrogation, intimidation, persuasion, charm or only a charisma attribute use the appropriate one when talking to a witness. If the Oracle has interventions or unexpected events, use them normally.

Cement Hypothesis

During the course of the investigation, many hypotheses will arise. Once you have a hypothesis of what happened that you feel is most likely, run a 6M Why/Why Not analysis on it. Each M, that supports the hypothesis (a Why) adds one point to the hypothesis score. Each M that contradicts the hypothesis (a Why Not) removes one point from the hypothesis score. Each M that neither adds nor contradicts the hypothesis doesn’t affect the hypothesis score.

The suspect. His character, does it fit the hypothesis?
Evidence (not the murder weapon, see Machine) that supports the hypothesis.
Means (Environment):
The crime scene. Are there signs that support the hypothesis? Struggle? Forced entry?
The reports, autopsy report, police reports, financial trail reports, do they support the hypothesis?
Machine (Murder Weapon):
The murder weapon, does it belong to the suspect? was it found on their possession? Is it their favorite tool? Is it a tool of their job?
The method of killing, does it support the hypothesis further? Could the suspect have committed the crime using this method? A slim young woman is unlikely to have strangled a heavyset wrestler.

Once the hypothesis score is set, any questions to the Oracle regarding the hypothesis from then on will have the following modifier:

Hypothesis Score Modifier
1 Very Unlikely
2 Unlikely
3 No Modifier
4 No Modifier
5 Likely
6 Very Likely

If a further Oracle answer modifies one of the 6M, adjust the hypothesis score respectively.

The adventure is considered complete with the Closure of the case. This can be a different thing regarding the objectives set at the start.
It could be a trial and you send it to the DA. It could be an occult ritual and you hunt down the demon. It could be a plea from the suspect.

Scene Example

  1. Story thread
    Let’s say I want to run a ’30s Murder investigation. I decide that my character is a police detective on homicide investigations. I will start my opening scene with the crime scene.

  2. Known information
    All the following question can be asked either with procedural Oracle questions, or generators, digital or tables. For the sake of the example I won’t be using any tools, just providing answers, to make it easier to showcase it.
    The following can be asked on the way to the crime scene, or before, during the assignment.
    Roll: What time of day is it?
    A: 10.00 am
    Table: Where is the crime scene?
    A: A mansion
    Table: Who called it in?
    A: Service maid
    Roll: When did she notify the police?
    A: 8.00 am
    since a service maid called in about a murder in a mansion, it’s likely they know the victim’s identity
    Q: Is the victim’s identity known?
    A: Yes
    Table: Who is it?
    A: The rich lord

  3. Obvious information
    The detective reaches the mansion.
    Q: Are they first responders?
    A: Yes
    which begs the question
    Table: Who opens the door?
    A: The butler
    Table: Where is the body?
    A: Living room, in an armchair next to the fireplace
    Q: Is there a weapon visible?
    A: Yes, and it’s next to the body
    Q: Is it a firearm?
    A: Yes
    Q: Is it a revolver?
    A: No, but, its a pistol, a semi-automatic
    Q: Is it near the hand?
    A: Yes
    Q: Is it the right hand?
    A: Yes
    this could look like a suicide
    Q: Is there a headshot wound?
    A: Yes

  4. Investigation information
    Detective succeeds on Moderate investigation roll, gaining 3 answers on the Oracle.
    Q: Is there an exit wound?
    A: No
    Q: Is there a flash burn on the head?
    A: False presupposition, there is too much blood to make it out
    Q: Is there any other wound?
    A: No, but it can’t be clearly seen

  5. Search information
    Detective succeeds on an Easy search roll, gaining answers on an out-of-sight but not hidden items
    Q: Are there shell casings?
    A: Yes, and, its two of them!
    so one shot missed, maybe during suicide there was a trembling hand, this means there’s a bullet somewhere
    Q: Is there a bullet hole?
    A: No, and there is no bullet strike either (no ricochet)

  6. Follow up information
    So maybe there is a window, and the bullet went out that way?
    Q: Is there a window?
    A: Yes, but, it’s not in the logical trajectory of the bullet
    something doesn’t fit here

  7. Field examination information
    Since it’s the ’30s I doubt there’s much of field examination kits going.
    Witness statements are taken here. Extra care must be taken when using a generator to define the NPCs. If I get a result that says that an NPC is a sleazy weasel, then that must be the feeling that the protagonist gets when talking to them, which could be far from the truth. A perception check is in order for any information given, to see if you can ask the Oracle if the NPC sounds truthful.
    I won’t go much into dialogues, maybe in a future update.

Now, the investigator has a series of things to look upon. For now, I will jump to the end, and skip the main part of the adventure, but we’ll suppose that the following has been gathered.

  • The victim left a suicide note
  • The victim had suicide tendencies according to separated-wife
  • The victim was rich and had properties according to lawyer
  • The victim’s doctor said he was getting better
  • The cook heard one gunshot, but maybe it was two together
  • The cook says he was preparing a chicken for the day’s meal at the time of murder
  • The butler heard one gunshot
  • The butler says he was in the library at the time of murder
  • The service maid was out in the stables with the stable boy
  • The victim was left handed according to the doctor
  • The forgery expert derived that the suicide note is genuine
  • The autopsy report revealed two bullets in the brain and no gunshot residue on the head
  • The lawyer said that the divorce hadn’t been finalized yet
  • According to victim’s best friend the wife was a schemer who spent too much, that’s why the victim wanted to divorce her
  • According to the butler the cook was stealing cash from the victim whenever he could find the opportunity

With the above and the clues from the initial crime scene, the detective is certain that this wasn’t a suicide.
Hypothesis: The wife used a suicide note she had kept from when the victim was in a bad shape and staged his murder. Due to the fact that she’s not a resident in the mansion anymore she must have had help. Considering that the butler knew the victim very well, he couldn’t have made such an obvious mistake such as planting the firearm in the wrong hand, so that leaves only the cook as a possibility.

6M Why/Why Not
The wife spent a lot of money and would be left out with a minimum allowance after the divorce.
Man supports the hypothesis.

Means (Environment)
2 shell casings were found away from the body, someone shot the victim from away.
Means supports the hypothesis.

A genuine suicide note was found which contradicts the hypothesis.
Material contradicts the hypothesis.

2 bullets were found in the head of the victim. The lack of GSR means that the shot was from afar. Measure supports the hypothesis.

Machine (Murder Weapon)
The murder weapon was an easy to use semi-auto pistol, in the ownership of the victim. It neither supports nor contradicts the hypothesis.

The wife was a schemer. Having an accomplice fits means she had access. The cook was a common thief.
Method supports the hypothesis.

So we have 4 points that support, 1 point that contradicts, and one that doesn’t support or contradict, for a final score of 3. The detective will try to intimidate the cook into confessing the crime saying that the wife gave him up, and will do the same to the wife. If anyone fails to the intimidation attempt, then we get to ask the Oracle with no modifier according to the score of 3, if the hypothesis stands, and possibly get a confession.