Kamala Harris has been facing criticism from fellow Democrats over her criminal justice record during her time as a top California prosecutor. During last month’s Democratic debate, for example, Tulsi Gabbard slammed Harris for blocking DNA testing that could have exonerated death row inmate Kevin Cooper while she was district attorney of San Francisco.

Cooper was convicted of murdering Douglas and Peggy Ryen, their 10-year old daughter Jessica, and 11-year-old Christopher Hughes, a family friend of the Ryens’, during a home invasion in the Chino Hills area in 1983. For the past 15 years, his attorneys have been fighting for advanced testing of DNA evidence which they claim could exonerate their client, a move that was opposed by Harris while she was attorney general of California. Last year, after the case was publicized by the New York Times’ Nick Kristof, Harris backtracked and told the paper that she felt “awful about this” and now supports the testing, but did not explain what prompted her change of heart.