The inquiry comes after Farah, 39, said in a documentary that a woman he didn't know brought him to the U.K. when he was about 8 years old and forced him to care for her children. He said he wasn't allowed to go to school until he was 12.

In the documentary, produced by the BBC and Red Bull Studios, Farah said his real name is Hussein Abdi Kahin. He said he was brought to Britain using fake travel documents that included his picture alongside the name Mohammed Farah, the name under which he won four Olympic gold medals and was knighted by Queen Elizabeth II.

“We are aware of reports in the media concerning Sir Mo Farah. No reports have been made to the MPS at this time,'' the police department said in a statement. “Specialist officers have opened an investigation and are currently assessing the available information.”

Farah previously said he moved to Britain with his parents as a refugee from Somalia. But in the documentary, he said his parents never came to the U.K.?

His father was killed by gunfire during unrest in Somalia when Farah was 4, according to the film. His mother and two brothers live on the family farm in Somaliland, a breakaway region of Somalia that is not internationally recognised.

Farah said in the documentary that physical education teacher Alan Watkinson helped him obtain U.K. citizenship under the name Mohamed Farah.?

The British government has said it won't take action against Farah for any potential violation of immigration laws.

Farah said he was proud to have represented Britain as an athlete but that his “proudest achievement will always be being a husband and father to my amazing family."

"I did this documentary for them, so they could understand more about the experiences that led us to becoming the family we are today," he said in a social media post. “Not every child will have the easiest start in life, but that doesn't mean they can't go on to achieve their dreams."