It is very important that you include facts from both sides. Sexual assault can often involve he-said-she-said arguments. It comes down to proving consent or lack of consent. Make sure there is a rape kit, a complaining witness, and proof of lack of consent. Unfortunately, the victim and suspect's sexual history is bound to come into play, as well as their general character and factors such as drug or alcohol usage at that time.
If you're still looking for a case with which to work, I would recommend looking at the Scottsboro trials. This case has the added element of race, and it's fairly clear the young black boys did not actually assault the white girl who made the accusations; however, it was the 1930s and the boys were found guilty before the trials ever started. This is the trial which also inspired Harper Lee's novel To Kill a Mockingbird.
The previous post has some excellent ideas on the structure of this assignment. An interesting case that you might want to investigate is that of Ronald Cotton. In 1984 Ronald Cotton was arrested for the rape of Jennifer Thompson. Thompson told investigators that she made a great effort to study her attacker in order to identify him. She chose Cotton out of a photo lineup and twice testified against him. She did this after seeing Bobby Poole who had bragged to inmates that he was the one who raped Thompson. Cotton was convicted on the strength of Thompson's testimony. After serving ten years, Cotton was released from prison after DNA testing showed that Bobby Poole was the actual rapist and that Ronald Cotton was innocent.
In summarizing a case (and with very little information to go on from your question) you would want to include the facts of the case itself - time, date, place, evidence present, victim's statement, interrogation or polygraph results, the criminal history of the accused, testimony of witnesses.
As it is a case involving sexual assault, include in the evidence summary if a standard sexual assault examination was carried out, and any specific evidence from that examination and its forensic analysis that is relevant to the case.
If the case has already gone to trial, you would want to summarize the key arguments for both the prosecution and the defense, and any legal opinions or comments about the verdict from the judge. You may also want to include the sentencing handed down if there was a conviction and any mitigating factors involved in it.