(CNN) The family of the controversial Harvard professor who commissioned photos of slaves say the university should give the photos to their descendants.

Forty-three direct descendants of Prof. Louis Agassiz signed a letter in support of the family of the enslaved man, Renty, and his daughter Delia, whose photos were commissioned by Agassiz in the 1850s.

Earlier this year, Tamara Lanier, a descendant of Renty, had filed suit against Harvard asking that the university turn over the images of Renty and to pay unspecified damages

After being named head of Harvard's newly created Lawrence School of Science, Agassiz became an advocate for polygenism -- the theory that the suit said was used to justify the enslavement of black people and, later, their segregation.

The photos, also referred to as daguerreotypes, are some of the earliest known photos of slaves.

In the photos, Renty was stripped naked and photographed from every angle "without consent, dignity, or compensation," according to the lawsuit, which was filed in Middlesex County Superior Court. Delia, stripped to the waist, posed next to him.

An enslaved African man named Renty and his daughter Delia were forced to pose for images commissioned by a Swiss-born Harvard professor in 1850.

"For Harvard to give the daguerreotypes to Ms. Lanier and her family would begin to make amends for its use of the photos as exhibits for the white supremacist theory Agassiz espoused," the letter from Agassiz's family said. "It is time for Harvard to recognize Renty and Delia as people. The daguerreotypes are, as Ms. Lanier has said, family photos."

One of Lanier's lawyers is civil rights attorney Ben Crump, who underscored the sentiments of the Agassiz family.

"With the Agassiz family's letter and their vocal support, along with the knowledge that it is the right and honest thing to do, we hope Harvard will finally face the ugly truth of its past and immediately return the images of Renty to Tammy Lanier, the great-great-great granddaughter of the African slave,"

In an email to CNN, Harvard spokeswoman Rachael Dane told CNN that while the university could not comment on the ongoing lawsuit, it "has and will continue to come to terms with and address its historic connection to slavery."

The lawsuit claims that Harvard has continued to profit off of the photos of Renty and Delia. For example, an image of Renty is used on the cover of a book called "From Site to Sight: Anthropology, Photography and the Power of Imagery," that is sold for $40.

"Does the University want to continue to gain from an image stolen from enslaved people?" the letter asks in part after mentioning the book. "Until Harvard commits to redress the harm it wrought, complicity will continue to define and mar its legacy. It is our hope that releasing the daguerreotypes will be a first step in a long overdue movement of reckoning and repair."