An Internal Revenue Service manager in Cincinnati singled out the first Tea Party case that prompted widespread targeting of conservative groups, and an agent from the same office developed the initial search criteria for the initiative, according to the House oversight committee's top Democrat.

Rep. Elijah E. Cummings of Maryland said that the new details should absolve the White House of blame for the issue and bring to a close House investigations.

The IRS has come under fire from Republicans since an inspector general report last month showed that the agency had singled out conservative groups seeking nonprofit tax status for scrutiny during the 2012 election cycle.

In a memo to his colleagues on the House Committee on Oversight and Government Reform, Cummings cited excerpts from transcripts of congressional interviews that appear to shed light on a previously unknown detail — namely, what prompted the IRS targeting in the first place.

The excerpts show that the effort began with a self-described "conservative Republican" manager from the Cincinnati office, who told congressional investigators that he sent the first Tea Party case to Washington on Feb. 25, 2010, to help determine whether the group should qualify for tax-exempt status.

A timeline from the inspector general's report listed an unidentified event on the same date as the genesis of the targeting effort, which came to focus on groups with names containing "Tea Party," "patriot" and "9/12," a term associated with conservative political commentator Glenn Beck.

A screening agent from the Cincinnati office told congressional investigators that he developed the initial search criteria after the ­manager asked him to identify additional cases, according to the excerpts.

"I noticed that there were hundreds of these things," the agent reportedly said about Tea Party groups he discovered on the Internet. "So some of the names I used — some of the terms — to find the tea parties. Tea party went by other names."

According to Cummings' memo, the IRS manager said no one from Washington ordered him to identify additional Tea Party cases. "No one said to make a search," he said, according to an excerpt.

Cummings said that the evidence suggests that "the case is solved" and that House investigators should move on. But Rep. Darrell Issa, R-Calif., chairman of the committee, said many questions remain unanswered.

The excerpts cited by Cummings "did not provide anything enlightening or contradict other witness accounts," Issa said in a ­statement.

Both sides on the committee have released partial transcripts of the congressional interviews to support their narratives. Both sides also have declined requests to ­provide the full transcripts.

The IRS on Monday replaced Holly Paz, an official who oversaw the Cincinnati division during the targeting campaign. The move is part of an IRS shake-up in the wake of the controversy.