Read our Privacy noticeA photographer who lured teenage girls with promises of modeling careers before sexually abusing them and producing child sexual abuse material has been sentenced to 40 years in federal prison. Robert Koester, 59, also known as Bert Kay, was sentenced this week in Oregon after pleading guilty to producing child sexual abuse material involving victims in Oregon and California. He later pleaded guilty in San Diego County to nearly two dozen felony charges, including rape, sexual assault and producing child sexual abuse material. Federal court records state investigators found child sexual abuse material involving victims on electronic devices seized from Koester's California apartment. "His violent abuse of these girls created scars they will carry their entire lives, and the images of that abuse will haunt them.