NEW YORK (CBSNewYork/AP) — New York University is apologizing for allowing donated bodies to wind up in mass graves meant for unclaimed and indigent bodies.

Several bodies donated to the university for medical science were buried on Hart Island despite having signed guarantees that their remains would be cremated and the ashes disposed of in a dignified manner.

Among those buried was Ruth P. Smith, a reproductive rights advocate who donated her body to the university for medical research upon her death. According to Ruth’s daughter, Gael Smith Arnold, she did not learn that her mother had been buried on Hart Island until a reporter from the New York Times gave her a heads up, WCBS 880 reported.

“I was very shocked,” Arnold said. 

University spokeswoman Lisa Greiner says the school has no idea how many donated cadavers wound up in the mass graves. She says officials didn’t know it was happening until the newspaper reported on it. She says the practice was related to confusing notification letters sent to surviving family members.

Greiner says all donated cadavers are now cremated, with the ashes returned to families or scattered in a crematory’s memorial garden.

(TM and © Copyright 2016 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2016 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)