According to the prisons, the systems are being used to improve security in the facilities and to combat fraud. Prisons can use the biometric identifier to track phone calls and find past communications that match the voice print of a particular person. The systems can also flag calls deemed to be suspicious to allow investigators to review the communications. According to The Intercept, the voice printing technologies were developed with grant money from the Department of Defense as a way to identify calls made by terrorists and other suspected criminals. The services have since been marketed to prisons to build databases of incarcerated people.

According to the report, some of the recordings taking place at prisons are made without the consent of the incarcerated. In one instance, The Intercept recounts the story of a prison in New York's Sing Sing prison who was told by a corrections counselor to read a set of phrases that would be recorded to create a voice print. If he refused, he was told he would lose phone access entirely and no longer be able to contact his family.

The voice printing technology, which is not discernibly different from the technology that enables consumer voice assistants to recognize voices, may not just be invading the privacy of people being kept behind bars. According to the report, officials from New York and Texas confirmed that agencies hold on to voice prints after the incarcerated are out of prison. Some counties also confirmed they could identify the voices of outside callers, meaning people who have not been accused of or committed a crime may still have their voice print recorded by the systems.