Republicans chastised the Justice Department on Thursday for failing to share information with Congress about its investigation into the targeting of conservative groups by the Internal Revenue Service. Lawmakers called anew for a special prosecutor to look into the matter.

The criticism during a House subcommittee meeting came as Deputy Attorney General James Cole, the Justice Department’s No. 2 official, said the investigation has been broadened to include the disappearance of emails from the computer of Lois Lerner, who formerly headed the IRS division that deals with tax-exempt organizations.

Rep. Jim Jordan, R-Ohio, chairman of the subcommittee on Economic Growth, Job Creation and Regulatory Affairs, told Cole that he had “serious concerns” about the investigation and asked what it would take for an independent prosecutor to be appointed.

He also demanded that prosecutors investigate why it took the IRS two months to publicly report the missing emails.

Jordan asked, “Are you going to look at the fact that the head of the agency that targeted conservative groups knew in April and didn’t tell us” until June?

Cole, who said the Justice Department didn’t learn about the email loss until after it was reported in the news media, said he did not know the reason for the two-month lag but that he expected it to be examined as part of the broader investigation.

“Crimes were committed. Regulations were violated. Rules were broken. And Americans’ constitutional rights were violated by Lois Lerner and perhaps others around her,” Rep. Darrell Issa, R-Calif., a leading Justice Department critic in the House, told Cole.

The panel’s top Democrat, Rep. Elijah Cummings of Maryland, defended the department, saying there was no evidence of obstruction. He said Republicans were “desperately searching” for a scandal. Documents have shown some liberal groups were also flagged.

Lerner, who refused to answer questions at two House committee hearings, has become a central figure in several congressional investigations into the handling of applications for tax-exempt status by tea party groups.

At both hearings, Lerner cited her Fifth Amendment right not to incriminate herself. In May, the Republican-led House voted to hold Lerner in contempt of Congress for refusing to testify.

The IRS revealed last month that it lost the emails in 2011 when Lerner’s computer crashed. IRS Commissioner John Koskinen has said he’s seen no evidence that anyone committed a crime in connection with the lost emails. There is no evidence that Lerner intentionally destroyed them, he said, adding that IRS has gone to great lengths trying to retrieve lost documents on her computer.

The disclosure by Lerner in May 2013 that the IRS had engaged in “inappropriate” targeting of conservatives set off a political firestorm that continues to flare in this election year.

Word that investigators are broadening their inquiry to include the missing emails comes as Republican lawmakers accuse the Obama administration of not cooperating with their investigation and failing to take the matter seriously enough.