The Anatomy of a Criminal Investigation

Discussion in 'Forensic Science' started by Forensics_Guy, Jul 12, 2006.

  1. Forensics_Guy

    Forensics_Guy Witness

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    The Anatomy of a Criminal Investigation

    There are three major parts to a criminal investigation, all three are popularized in television shows. The first part is the investigation of the crimes after the crime. The second part is the scientific analysis of evidence gathered during the investigation. The third and last part is the legal battle waged in the courtroom between the attorneys for the state and the defense, using different interpretations of the findings gathered during the first part, and the opinions generated in the second part.

    The investigation is most commonly carried out by local law enforcement agencies. The manner is which law enforcement agencies is under constant scrutiny by people both inside and outside of that field. The investigation generally ends when a suspect is identified, and sufficient evidence has been collected to convince the police of the suspects guilt. But investigation can also take place by private investigators on behalf of the defense, as well as investigators acting on behalf of the state attorney. All three groups can collect evidence as as result of visiting the scene (the police usually have first dibs), and interviewing witnesses. The primary job of the police agency is of course to maintain/improve public safety. The primary job of the defense investigators is to help the defendant prove their innocence. The primary job of the state attorney's investigators is to help the state prove the guilt of the defendant.

    The scientific analysis has traditionally been carried out by police laboratories. More and more independent laboratories are starting to reanalyze, if not analyze, the evidence as well. Generally police investigators have a good working relationship with the police crime laboratory. The result is that if backlogs are not too great, the scientist can actually help detectives with an ongoing investigation. The scientist's main job is to examine the evidence with impartiality, and report conclusions/opinions based solely on the physical evidence they examined, and not on reported tales of the incident.

    In the courtroom arena, through a series of rules and precedents that few people fully understand, the attorneys for both sides try to convince the trier of fact that there is either enough (in the case for the state) or not enough (in the case for the defense) evidence to find the defendant guilty. Both sides will call upon their own witnesses to support their claim during "direct examination". The witness if then subject to "cross-examination" by opposing council. Usually the original side is allowed to "re-direct" any questions brought up during cross-examination. In some jurisdictions the trier of fact is allowed to ask their own questions, which can lead to another round of direct/cross/re-direct questions from the attorneys. During direct examination the attorney brings out facts/opinions that support their claim, and might even bring out fact/opinions that hurt their claims in attempts to minimize the damage those facts might do to their case in a series of questions they control. During cross-examination the attorney can either try to attack the qualifications of the witness to try and decrease the amount of weight the trier of fact will give to that witness's testimony/opinions. The attorney might also try and show how the scenarios the first attorney brought up might not be the only possible scenarios that could explain the evidence collected.
     
  2. beautiful_loser

    beautiful_loser Pathologist

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    You forgot the preliminary inquiry, in which experts may be called. On the show when they're called to the stand it's usually in a preliminary inquiry, to determine if there is enough evidence to go to trial. Sometimes they don't even need to take the stand, their reports (at least in Canada) can be entered into evidence and they don't need to show up at all.
     
  3. SamStokes

    SamStokes Police Officer

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    Yeah but in the UK i think this works somewhat the same, but, um i don't no, anyway good bit of info there from ForensicsGuy but yeah you had missed out the preliminary inquiry which can somewhat be the most important part of the investigation to put the defendent away.
    Apart from collecting the evidence of course without that you wouldn't be able to arrest the person.
    But isn't this right, if any piece of evidence is lost then recovered this can't stand up in court due to the fact someone could have tampered with it.
    Doesn't count for prints or swabs as they are recollected.
    sorry i'll stop rambling on know!
     
  4. Forensics_Guy

    Forensics_Guy Witness

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    While prelim (grand jury whatever you want to call them) are important, people considering going into the forensics field shouldn't be very concerned with them.
    In thousands of cases I've been envolved with, and over 50 trials (mostly homicides), I've never been called into testify on a prelim.
    On the few evidentiary hearings (hearings before the real trial to answer to a defense motion to supress evidence) they are a lot less formal, and generally the judge only. In those cases everyone behaves a lot more because the theatrics of the defense attorney aren't well received by the judge.
     
  5. SamStokes

    SamStokes Police Officer

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    Um i was told to take up lots of things that considers speaking infront of people and my friend recommeended joining Drama Club (Not my strongest point) to help you to be able to speak aloud infront of people whilst making sense.
     
  6. beautiful_loser

    beautiful_loser Pathologist

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    Any evidence, including prints and swabs, must be properly accounted for from the time it is collected to the time it appears in court. If it isn't/can't be, it is inadmissible.

    The preliminary inquiry determines if the evidence that the prosecution has is enough to go to trial, if it is admissible. If anything else comes up, the court will hold a voire dire to determine the admissibility of the evidence, which, as forensicsguy said, is presided over by only a judge.
     

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