Washington (CNN) Fiona Hill, President Donald Trump's former top Russia adviser, will explain to Congress when she testifies next week that she was unaware of some aspects of the escalating Ukraine scandal, according to a source close with Hill who spoke to her Thursday.

Hill has been subpoenaed and is working with her lawyer on logistics.

She officially departed her role in August, though she had handed over most of her responsibilities in July, but was involved as Rudy Giuliani was making public pronouncements about Ukraine.

Hill has kept a low profile in recent weeks in England with her mother.

CNN has reached out to her attorney.

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