Latifa bint Mohammed Al Maktoum, the daughter of Dubai ruler and UAE Prime Minister Sheikh Mohammed bin Rashid Al Maktoum, has sent a letter to police in the U.K. asking them to investigate the alleged kidnapping of her older sister, Princess Shamsa, from Britain in 2000.​​

"In the summer of 2000 Shamsa escaped the family vacation house in England. She was 18 years old ... and of sound mind," Princess Latifa, who has also claimed she is being held hostage, wrote in a letter sent to CNN by her friend David Haigh, a campaigner for her release and part of Detained International, a legal advocacy NGO.

"She was enslaved and oppressed and suffered physical abuse at the hands of family members ... She wanted to seek asylum in the U.K. where she has family permanently living there. After a few months, she was kidnapped ... She was dragged from the street kicking and screaming. She was tranquilized and flown back to Dubai," Latifa wrote in the document dated February 2018.

The princess added her sister was tortured, "kept incommunicado with no release date, trial, or charge."

"She was tortured by getting her feet caned which is something I experienced myself with my own imprisonment," she wrote.

"Her ultimate goal is to be an emancipated person, to live with dignity, to have freedom of choice and freedom of movement ... She wants the basic rights that all human beings are entitled to," the princess continued.

The princess said her sister has "strong links to England" and was "abducted in an illegal manner, on U.K. soil."

"All I ask of you is to please give attention on her case because it could get her freedom, which is the only thing that she wants in life," she added.

In a statement sent to CNN, Cambridgeshire Police confirmed it has received a letter, "dated February 2018 in relation to this case which will be looked at as part of the ongoing review."

The force also said it is investigating the recent BBC Panorama documentary, in which Latifa herself claims to be held hostage in Dubai.

The U.K. Foreign Office declined to comment on Thursday.

A recent statement by her family said coverage of Latifa's situation "is not reflective of the actual position," according to the United Arab Emirates embassy in London.

The letter was obtained and delivered to the police by one of Latifa's cousins and Haigh.

The group also submitted a "transcript of a number of video statements from Sheikha Latifa," which were obtained by "smuggling, with great difficulty and danger, a mobile phone into the Dubai jail of Sheikha Latifa," Haigh said in the letter sent to police and shared with CNN, using her Arabic title.

"Contact [with Latifa] was maintained throughout the majority of 2019 and 2020. Contact was lost in the second half of 2020," Haigh said.

The group also claims it has evidence that one British citizen was involved in the kidnapping of Princess Shamsa.

"We were not able to release such evidence previously due to what we believed was an unacceptable risk to the life and safety of Sheikha Latifa. However, now that contact has been lost, we are gravely concerned for her life and safety and decided to take the step to release the evidence obtained," Haigh added.