On December 19, Nicki Minaj is scheduled to play a holiday show in the capital of Angola for the communications company Unitel.But according to the Human Rights Foundation , Unitel is "controlled by the family of dictator José Eduardo dos Santos."A press release from HRF notes, "José Eduardo dos Santos has ruled the southwestern African country of Angola with an iron fist for more than three decades. He installed his family as owners of the country’s major businesses, and ordered the routine harassment, arrest, and execution of politicians, journalists, activists, and students who oppose the government and expose its corruption."The Human Rights Foundation's concern over Minaj playing for Unitel and, by extension, dos Santos, has prompted them to write a letter to the Grammy-nominated singer urging her to cancel the appearance.Penned by Thor Halvorssen, president of the Human Rights Foundation, and addressed directly to Minaj, the letter discusses the long-standing crisis in Angola in what he describes as a "brutal three-decade authoritarian rule" by the dos Santos family.Halvorssen pleads with Minaj to back out, stating, "The payment you are receiving from your Angolan sponsors is the result of government corruption and human rights violations."He adds, "Ms. Minaj, you are well known for being involved with charities such as the Get Schooled Foundation, which helps motivate young people to graduate from high school and succeed in college. Yet, if you move forward with this performance for the dictator and his family, you will be in league with the people stealing educational resources and opportunity from young Angolans."The letter, which you can read in full here , doesn't hold back from taking a strong stance against Minaj's decision to play the Angola show. Minaj has yet to respond on social media to HRF's call to action.