One of three victims kidnapped, imprisoned, raped, and tortured for a decade in the Cleveland, Ohio home of Ariel Castro wrote a handwritten note to Cleveland police thanking them for their gratitude. Michelle Knight, 32, is also the only victim that testified in court directly against Castro Thursday.

Knight, who was kidnapped by Castro when she was 22, suffered the worst abuse out of the two other captors, Amanda Berry and Gina DeJesus. Castro allegedly impregnated Knight five times and then forced a miscarriage by beating and starving her.

Despite her horrible traumas, Knight says she is now stronger than ever. Cleveland Police posted a copy of her note to their Facebook page Wednesday. According to Huffington Post, she wrote,

“Life is tough, but I’m tougher! Just when the caterpillar thought the world was over, she became a butterfly.”

According to ABC News when Cleveland police rescued the three women on May 6, they thought Knight was a young girl because she jumped on the police officers with excitement and was extremely underweight due to malnutrition. She also had trouble breathing because she was so scared.

Knight was also the only captor that appeared in court Thursday and read her personal statement to Castro, before he was found guilty and sentenced to life in prison plus 1,000 years.