The mystery surrounding who killed Chandra Levy seemed to end with the 2010 conviction of Ingmar Guandique for the crime. But now Guandique’s attorneys have hinted that they could seek a new trial, saying that the government’s case against their client was “predicated on a lie,” reports the AP:

The arguments from attorneys for Ingmar Guandique were included in records of previously closed hearings in the case that were unsealed Tuesday.

Levy was an intern for the U.S. Bureau of Prisons whose 2001 murder attracted attention because of her romantic relationship with a California congressman. Guandique is an illegal immigrant from El Salvador and was convicted in 2010. He is serving a 60-year prison sentence.

The case hinged on a jailhouse informant who said Guandique had confessed to killing Levy. The documents show prosecutors learned a year ago about a problem with a witness but it’s not clear if that person was the informant.

No evidence was ever presented to definitively link Guandique to Levy’s 2002 killing, but prosecutors said that the murder followed a pattern of attacks by Guandique on women running through Rock Creek Park. Guandique’s lawyers have been seeking an appeal since at least 2011, but this new information might make a new trial more likely.