"I feel the FBI and every other law enforcement agency underestimated me," Barnett said.
She also admitted that when she was abroad, she feared getting caught "every day".
FBI agent Chris Quick told 48 Hours law enforcement struggled to catch Barnett.
"Dorothy Lee was very equipped in running from the law. She thought about this. She was planned and determined," he said.
"Our investigation spanned the United States and the globe," he told CBS.
"I thought this was going to be one of those unsolved mysteries that would never be solved."
Barnett adopted the identity and false name of Alex Geldenhuys. And unbeknownst to Savanna, she became Samantha Geldenhuys.
When on the run, Barnett kept a secret diary for her daughter, planning one day to tell her the whole story of her life.
Savanna turned 22 in May and was now known as Samantha Geldenhuys.
She only learned about her identity and her mother's life on the run after Barnett was arrested in Queensland in late 2013.
"I knew my mum as Alex my entire life," Samantha told 48 Hours. "But in reality she wasn't Alex at all."
Barnett was finally caught after the FBI received a tip in 2011 that she was living in Queensland.
"I realised that it was all up. That they'd found me," Barnett says.
"And I knew that I would have to face the consequences of what I did 20 years before."
- NZME News Service and The Sunshine Coast Daily
