FILE PHOTO: U.S. Democratic presidential candidate and U.S. Senator Kamala Harris (D-CA) speaks during a Fourth of July House Party in Indianola, Iowa, U.S., July 4, 2019. REUTERS/Scott Morgan/File Photo

WASHINGTON (Reuters) - U.S. Senator Kamala Harris on Thursday pledged the nation’s backlog of rape kits needing review would be processed by the end of her first four-year term if elected president.

Harris estimated she would invest $1 billion to eliminate the backlog, which she said would cover an estimated 225,000 kits that remain untested.

Rape kits are collected when a victim reports an assault and DNA or other physical evidence is collected. State crime labs have built huge backlogs of untested kits, some of which may be able to identify assailants already in the system.

Harris would require states that receive her proposed funding to also implement four sets of reforms.

States would have to begin tracking and disclosing the number of untested kits, test newly collected kits in a short time frame, track kits and let victims know the status of testing and provide law enforcement agencies, particularly in rural areas, with more kits.

Harris has tried to capitalize on her time overseeing the prosecution of crimes while California ‘s attorney general before she was elected to represent the state in the U.S. Senate.

While the role has drawn criticism that she was overzealous in prosecuting some cases, particularly drug offenses and those that more heavily affect black people, she has also tried to use her prosecutorial record as an asset and argues it positions her to better challenge Republican President Donald Trump.

“The federal government can and should prioritize justice for survivors of sex abuse, assault and rape,” Harris said in a statement. “As California’s attorney general, I committed resources and attention to clearing a backlog of 1,300 untested rape kits at state-run labs, and we got it done within my first year in office. We need the same focus at the national level to pursue justice and help hold predators accountable.”