About 80 percent of the children in the abusive images are female, and 91 percent appear to be children under the age of 12. Prosecution is difficult because multiple international servers are used, sometimes to transmit the images in fragments to evade the law.[54] Some child pornographers also circumvent detection by using viruses to illegally gain control of computers on which they remotely store child pornography. In one case, a Massachusetts man was charged with possession of child pornography when hackers used his computer to access pornographic sites and store pornographic pictures without his knowledge.[55] The U.S. Court of Appeals for the Tenth Circuit has ruled that if a user downloads child pornography from a file sharing network and possesses it in his "shared folder" without configuring the software to not share that content, he can be charged with distributing child pornography.[56]