Authorities say the plea agreement includes a 15-year prison sentence for 45-year-old Valerio V. Alexander. According to court documents, investigators received a tip that a 16-year-old child had been the victim of sex trafficking. Authorities say further investigation found that Alexander had taken photographs of the victim in February 2013 and used the pictures to create online advertisements for prostitution. Federal Agents arrested Alexander March 8. A federal grand jury indicted another person in the case. Thomasina Howard pleaded guilty on August 9, 2013 to one count of conspiracy to commit sex trafficking of children. Her sentencing has been scheduled for February 13.