General Motors Co. Chief Executive Mary Barra is scheduled to testify on April 1 to a U.S. House of Representatives panel investigating the company's long-running problem with defective ignition switches that have been linked to 12 deaths, the committee said on Thursday.

House Energy and Commerce Committee leaders also said they had invited National Highway Traffic Safety Administration acting Administrator David Friedman to testify at the hearing.

This will be the first in what could be a series of hearings by the House panel that began an investigation after GM's decision to recall 1.6 million of its vehicles because of the ignition problem that first surfaced more than a decade ago.

While the defect problem began long before Barra and Friedman entered their current positions, their testimony, said committee Chairman Fred Upton, "will be essential to getting answers about what went wrong."

The hearing will be conducted by the panel's Oversight and Investigations subcommittee.