Sens. Cory Booker and Mike Lee, a year after forming a bipartisan coalition to pass the First Step Act, Monday noted that the law to reverse harsh mandatory sentencing guidelines is working, but Booker said there is still a long way to go toward equality.

"Ninety percent of the people being liberated right now are African Americans," the New Jersey Democrat, a candidate for the 2020 presidential nomination, told "CBS This Morning" in an interview with former Sen. Jeff Flake, now a network contributor.

"We live in a nation where our criminal justice system is still deeply biased against low-income people, against minorities, and this was a step," he added. "There's an anguish in my community."

The law was signed by President Donald Trump last year. Friday, the Justice Department released more than 3,000 federal inmates because of the measure. Most of those released were drug offenders.

Lee, R-Utah, said he wanted to reform the criminal justice system because as a former prosecutor, he "saw a number of abuses of federal law."

Booker said their teamwork on the bill shows Capitol Hill relationships can sometimes be surprising.

"I'm sitting next to a guy from Utah, not the most diverse state, but for him to have a sincere concern that we have more African Americans under criminal supervision than all the slaves in 1850, and understand the racial dynamics here, he and I had a real friendship," said Booker.

They also said they had Trump's son-in-law and adviser Jared Kushner behind the bill and without him, "we couldn't have gotten this passed," said Lee.