The prosecution used many forms of communication in order to convey their case to the jury. They used verbal communications of course when they made opening and closing statements, questioned witnesses before and during the trial, had objections, and when they put their case together. Before they went to trial they had to use multiple means of communication to gather evidence to present to the jury. They had to speak to the police investigators to even know if there was a case to try, and then they had to speak with investigators in order to gather all the evidence necessary to go to trial.
They also had to get police reports, witness statements, and warrants to proceed further in the case. This was a form of written communication that was utilized by the prosecution. Once there was a case to prosecute, the prosecution had various legal documents to peruse through to make their case against the defense. Some of the legal documents included police reports, warrants, witness statements, and statements made by the defendant. There are also records of police interviews with Casey Anthony, both written and tape recorded.
There are also written transcripts of recorded jail conversations between Casey and her family. The prosecution must also prepare its witnesses for the stand and the defenses cross-examination, which requires both nonverbal and verbal communications again. By these accounts, it is accurate to say that the prosecution uses many forms of communication to present their case. They even look for non-verbal cues from witnesses and even the defendant herself, such as, eye contact, or the lack thereof, and facial and body expressions.