Attorney General William Barr has recused himself from overseeing the Justice Department’s investigation into Boeing Co. that’s unfolding in the wake of two crashes that killed 346 people, according to a senior department official.

Barr is recused from the matter because his former law firm is representing Boeing, the official said. Boeing had no immediate comment on the matter.

The attorney general’s recusal removes a key decision-maker in a criminal investigation that seeks to determine whether the Chicago-based company and federal regulators gave short shrift to safety concerns while designing and certifying the 737 Max. Federal prosecutors have subpoenaed records related to the jet. They recently expanded their investigation to include a plant in South Carolina, which produced the 787 Dreamliner, people familiar with the probe have said.

The widening investigation by federal prosecutors adds to the pressure on the manufacturer, which also faces civil and congressional inquiries into the Max, its bestselling jet, and software linked to the two fatal crashes — in Indonesia last October and Ethiopia in March.

It is the second time this week that Barr has taken himself out of an investigation over ties to Kirkland & Ellis LLP, where he worked before being nominated by President Donald Trump to run the Justice Department.

On Tuesday, Barr said he wouldn’t be involved in an investigation into the handling of Jeffrey Epstein’s non-prosecution deal in 2007 with the U.S. Attorney’s Office in Miami because Kirkland & Ellis lawyers, including Ken Starr, represented the billionaire fund manager in a deal that has since come under scrutiny. Barr said he wouldn’t recuse from the current case against Epstein, filed July 2 in federal court in Manhattan, because Kirkland & Ellis isn’t involved in that one.

Barr hasn’t recused himself from all matters involving his former law firm. In April, he received an ethics waiver allowing him to continue to oversee the government’s investigation into corruption and fraud involving Malaysia’s investment fund 1MDB. In that matter, Kirkland & Ellis is representing Goldman Sachs Group Inc.

In the 1MDB matter, Barr said the Justice Department’s criminal division requested that he seek the waiver.

–With assistance from Julie Johnsson.