DNA expert in the Spanish Interior Ministry’s Comisaría General Policía Científica and research collaborator at the DNA laboratory of the University of Santiago de Compostela. Prieto is a member of the executive commitee of the International Society for Forensic Genetics (ISFG), a forensic consultant with the ICRC and member of the Editorial Board of the academic journal, Forensic Science International: Genetics.

She has been a member of the Spanish National Commission on DNA Analysis with Forensic Purposes and a member of the DNA Commission of the International Society for Forensic Genetics (ISFG). From 2008 to 2020, Prieto served as President and Vice-President of the Spanish and Portuguese Working Group of the International Society for Forensic Genetics (GHEP-ISFG). During the Spanish presidency of the European Union, in 1995, she was a member of the Scientific and Technical Police Delegation Group.

Prieto was a researcher at Instituto Universitario de Investigación en Ciencias Policiales (IUICP) and at Centro Apícola Regional de Marchamalo, in Spain. 

Some of her latest publications are Mass Identifications: statistical methods in forensic genetics (Academic Press, 2021, with Kling, Egeland and Tillmar), Valoración de la prueba de ADN en las identificaciones a gran escala de personas desaparecidas (2021, with Ruiz, Hernandis and Carracedo), Interpretando la genética forense (2019).