President Barack Obama has ordered a new review of a commutation request by Clarence Aaron, a first-time offender sentenced to three concurrent life sentences, according to a new report by ProPublica.

Obama also directed the Justice Department to review recommendations for presidential pardons. The Office of Pardon Attorney, which decides which cases to recommend for clemency, has come under scrutiny since a December joint report from The Washington Post and ProPublica uncovered a racial disparity in pardons. The report found that whites were four times more likely to be pardoned than minorities, even though more than 60 percent of the prison population is non-white.

The Justice Department has been aggressive in pursuing questions of civil rights violations, particularly those related to racial bias, under the Obama administration. In the past three years, the department’s civil rights division has filed more criminal civil rights cases than during any other period in its history,  according to Attorney General Eric Holder, who has underscored the point repeatedly in remarks to civil rights groups.

Aaron’s case has drawn support from members of Congress and civil-rights advocates, who say his sentence is unduly harsh and should be reviewed, particularly in light of the pattern of racial disparity revealed in the pardon attorney’s recommendations.

Here’s his story: Aaron was friends with other kids who were selling drugs. Aaron drove them around and was paid for his work, but never bought, sold or acquired any cocaine. But under a mandatory minimum sentencing law, the lowest-ranking person in an alleged crime can be slapped with the maximum sentence.

When they were caught, four young men involved in the drug deals testified against Aaron to avoid life sentences. Only one of them is still in prison, set to be released in two years.

Aaron, currently in a federal prison in Alabama, was sentenced in 1993 and will never be released — unless a president decides to pardon him. (Read FRONTLINE’s interview with Aaron here.)

For a time, Aaron’s case for a pardon looked promising. The judge who handed down the sentence and the prosecutor in his case both backed the move. But in 2008, the pardon attorney recommended to President George W. Bush that a pardon be denied — although he didn’t mention that Aaron’s request was backed by a judge and a prosecutor.

Aaron filed again in 2010, and that request is still pending. (ProPublica has a full timeline of Aaron’s clemency quest.)

FRONTLINE viewers met Aaron in our 1999 film Snitch, which explored how informants — people who testify to put others behind bars — have become a key part of prosecutors’ strategy in the drug war.

Sarah Childress, Former Series Senior Editor, FRONTLINE