Strohmeyer's Injustice

On the 27th of May in 1997, an 18-year-old, high school senior, Jeremy Joseph Strohmeyer, raped, beat, and strangled the seven-year-old, Sherrice Iverson to death in the Primm Valley Hotel Arcade. Strohmeyer was charged, 15 months later, with first-degree murder, first-degree kidnapping, and sexual assault on a minor. Along with Strohmeyer, that night, was his friend, David Cash, however, he got away with no charges, how so?
Hours before the murder occurred, Sherrice, her older brother, and her father arrived in Primm Valley around midnight, soon after, Sherrice’s father began gambling at the hotels casino and was later paged by security, they told him that his daughter was found wandering alone. Sherrice’s father then sent Harold, Sherrice’s 14-year-old brother, to retrieve her, security warned Harold not to come back without an adult. Sherrice’s family was told three times that they needed to keep an eye on her, however, the family failed to do so once again.
The arcade’s surveillance cameras saw Sherrice playing

David Cash was not charged with anything, the police even confirmed that he did not do anything wrong, however, college classmates, community members, mothers, radio hosts, and many others were furious and demanded that something needed to be done. They tried to get him kicked out of college, arrested, and even create a law requiring Samaritans to intervene and report crime. However, all efforts failed, Cash now lives his life with the haunting images of a friend raping, beating, and killing a young girl. But why? Why would Cash just sit back and stay quiet while this crime was going on? I believe that Cash thought if he notified the police, that he would be sentenced to jail for be a part of the crime, he was frightened, in my eyes, however, he tells later that he saw this felony taking place, yet still did not receive any punishment, which puzzles me. My other theory is that he simply wanted to protect his