While it would be nice to think that every rape victim should go to the police and report the crime, even that action doesn't assure that the case will make it to trial, or even that the evidence will be processed:
"Every two minutes, someone is sexually assaulted in the United States. With the crime of sexual assault, the victims body is a part of the crime scene. When the victim reports the assault to the police, a hospital or rape crisis center, a doctor or nurse will photograph, swab and conduct an invasive and exhaustive examination of the victims entire body for DNA evidence left behind by the attackera process that takes four to six hours to complete. That evidence is collected and preserved in a sexual assault evidence kit, commonly referred to as a rape kit.
When tested, DNA evidence contained inside rape kits can be an incredibly powerful tool to solve and prevent crime. It can identify an unknown assailant and confirm the presence of a known suspect. It can affirm the survivor's account of the attack and discredit the suspect. It can connect the suspect to other crime scenes. It can exonerate innocent suspects.
To accomplish these things, however, rape kits must be tested.
In the past, the federal government estimated that hundreds of thousands of rape kits sit untested in police and crime storage facilities across the country in what is known as the rape kit backlog. Each kit represents a lost opportunity to bring healing and justice to a survivor of sexual violence. "
- See more at:
http://www.endthebacklog.org/backlog/what-backlog#sthash.d4NiTWhp.dpuf
And from Wikipedia:
"According to a 2009 report by Human Rights Watch, Los Angeles, California has the largest known rape kit backlog in the United States, with at least 12,669 languishing in storage facilities of the Los Angeles Police Department, Los Angeles County Sheriff's Department, and 47 independent police departments in Los Angeles County, and "smaller, but not inconsiderable" backlogs residing at police crime labs. These backlogs consist of both kits stored in evidence storage facilities, for which DNA analysis is not requested by investigating detectives, and those submitted for testing at crime lab facilities, but which have not been tested in a timely manner. Although authorities have struggled to address the backlog problem, their attempts have reportedly been hampered by funding issues and politics. As a consequence of these backlogs, assault survivors are often not informed of the status of their rape kit or their case.["Testing Justice". Human Rights Watch. May 31, 2009]