May 3 (The Times) : An FBI translator with top security clearance married the Islamic State terrorist she was assigned to investigate, court documents have revealed.

Daniela Greene, 38, an FBI linguist, lied to her bosses and went to Syria in 2014 to marry an Isis recruiter who had previously been a rapper in Germany.

Within weeks, she regretted her decision to live with Denis Cuspert, who used the stage name Deso Dogg and became Abu Talha al-Almani as an Isis propagandist and recruiter. German intelligence described him as “something like a pop star of jihad”.

Ms Greene allegedly warned Cuspert that he was being investigated by the FBI. She eventually returned to the US, and was sentenced to two years in prison after agreeing to co-operate with an investigation, according to CNN. She was released last summer.

The case is an embarrassment for the FBI, raising questions over its security vetting. It has also led to suggestions that the Department of Justice was unusually lenient towards Ms Greene, whose case is still shrouded in secrecy.

Ms Greene “violated the public trust, the trust of the officials who granted her security clearance and the trust of those with whom she worked,” said Thomas Gillice, a lawyer for the US Attorney’s Office in Washington, where Ms Greene was charged and pleaded guilty to making false statements. Prosecutors had argued that her behaviour was deserving of “severe punishment” for endangering national security.

Ms Greene, who was born in Czechoslovakia, was already married to a US soldier when she went to Syria.

Cuspert is believed to be still at large in Syria. The Pentagon recanted a 2015 claim that he had been killed in an air strike in Raqqa.

Before going to Syria to fight in the civil war, Cuspert had had minor music success as Deso Dogg, once touring with DMX, an American rapper. His lyrics had celebrated violence and he had been arrested several times in Germany. On his 2009 album Angels Cry Black Blood he rapped: “The euro, the dollar, we can recognise the enemy/ For oil and for power, our homes will burn/ Guantánamo Bay is lousy as an animal laboratory/ Muslims are tormented.”

Ms Greene, who joined the FBI as a German translator in 2011, was assigned to investigate Cuspert in January 2014. She was described as a hard worker with a history degree. During the investigation, Ms Greene identified online accounts, phone numbers and Skype accounts used by Cuspert.

In June, she informed the FBI that she was going to Germany to see her parents, but instead travelled to Syria to marry him. Within a month, she expressed regret and escaped in August 2014. She was arrested when she arrived back in the US. Shawn Moore, her lawyer, told CNN: “She was just a well-meaning person that got [mixed] up in something way over her head.”