On Monday, Democratic presidential candidate Julián Castro visited a jail in Washington, DC, to have a conversation with those who are incarcerated about criminal justice reform.

The former Secretary of House and Urban Development wrote on Twitter that he visited with the men “to hear about their experiences, barriers they face and what they need to succeed.”

During the discussion, Castro asked what the men wished that people in power knew about imprisonment. According to him, one person responded, “mental health is the key thing.”

“We can’t continue to depend on the carceral system to provide mental health care, we need coverage for everyone, and community-led diversion programs,” he tweeted.

Last week, the Mexican-American candidate released his criminal justice platform, which includes investing in programs that have an “emphasis on conflict-resolution, trauma-informed care and community healing.” Additionally, one of the ways he hopes to tackle police violence is through promoting non-armed responses to 911 calls by establishing partnerships between mental health units and other first responders, including crisis intervention services by medics, counselors and social workers, rather than armed officers.

Castro’s proposal, released on Wednesday, aims to create “a wholesale reversal of damage” from the policies that led to mass incarceration following the 1994 federal crime bill. Called a “First Chance Plan,” it focuses on creating opportunities that can prevent crimes by addressing multiple factors, including housing, pre-K to college education, job training and foster care reform. Other forms of crime prevention include addressing police violence and legalizing marijuana.

The candidate’s platform also focuses on restorative justice, with plans to end cash bail, limit pre-trial detention to a last resort, end solitary confinement for punitive purposes and close for-profit prisons, as well as creating post-incarceration programs and plans that advise and assist those who are formerly incarcerated through “second-chance centers,” financial aid, restoring voting rights for people with felonies and providing clemency for nonviolent offenders.

Castro has been one of the only presidential candidates to speak out against police violence, calling it a form of gun violence earlier this month and also releasing a plan for policing reform.

Last week, the candidate announced that, despite his celebrated progressive vision for the country, particularly when it comes to criminal justice and immigration reform, he may be forced to drop out of the race due to fundraising difficulties.