Write a thesis that states your main point. For example, if you are writing about an investigation that was derailed when the officers obtained evidence unlawfully, your thesis may be "Had the investigating officers followed the law, even though it would have slowed the investigation initially, they would have been able to convict the suspect."
Find evidence from the case to support your thesis. Choose three or more points depending on the assignment's length. For example, you may choose the fact that the judge threw DNA evidence against the suspect out of court because investigators obtained it unlawfully, the investigators found witness testimony that was not enough to sway the jury on its own and the jury did not consider the testifying police officers to be trustworthy.
Organize your supporting points into a logical order, and write each of them as a heading for a section, with blank space underneath. Logical organization could be chronological, most important to least important or most general to most specific. Choose to write the points as words or sentences, for example "DNA evidence" or "Conclusive DNA evidence was unusable," depending on which is more helpful for you.
Find details, statistics, anecdotes and quotes from the transcript of the trial or other research sources to back up each of your points and explain why they support your thesis. Write them as words or sentences under their headings. For example, quote the defense attorney's statement to the jury that the police could not be trusted and may have been biased against his client.
Write your main conclusion, tying your points back to your thesis. For example, conclude this paper with "This case demonstrates the vital importance of following the letter of the law in a criminal investigation: The detectives had sufficient proof for a conviction, but because some of it was inadmissible, the jury found the suspect not guilty." When you write the paper, expand this into a full paragraph, referencing all your major points.