The Internal Revenue Service's scrutiny of conservative groups went beyond those with "tea party" or "patriot" in their names—as the agency admitted Friday—to also include ones worried about government spending, debt or taxes, and even ones that lobbied to "make America a better place to live," according to new details of a government probe.

The investigation also revealed that a high-ranking IRS official knew as early as mid-2011 that conservative groups were being inappropriately targeted—nearly a year before then-IRS Commissioner Douglas Shulman told a congressional committee the agency wasn't targeting conservative groups.

The new disclosures are likely to inflame a widening controversy over IRS handling of dozens of applications by tea-party, patriot and other conservative groups for tax-exempt status.

The details emerged from disclosures to congressional investigators by the Treasury Inspector General for Tax Administration. The findings, which were reviewed by The Wall Street Journal, don't make clear who came up with the idea to give extra scrutiny to the conservative groups.

The inspector general's office has been conducting an audit of the IRS's handling of the applications process and is expected to release a report this week. The audit follows complaints last year by numerous tea-party and other conservative groups that they had been singled out and subjected to excessive and inappropriate questioning. Many groups say they were asked for lists of their donors and other sensitive information.