Two years after being dragged through an embarrassing scandal stemming from allegations that Lois Lerner, a senior Internal Revenue Service official, wrongfully targeted conservative groups, a new bipartisan report released Wednesday seemed split on the root cause.

Republicans placed the blame for the scandal on Lerner, who used to head the division that processes applications for tax-exempt status.

The report claims Lerner waited nearly two years before notifying her supervisors about the massive delays in the processing of applications.

"This bipartisan investigation shows gross mismanagement at the highest levels of the IRS and confirms an unacceptable truth: that the IRS is prone to abuse," said Sen. Orrin Hatch, R-Utah, chairman of the Finance Committee.

"The Committee found evidence that the (Obama) administration's political agenda guided the IRS's actions with respect to their treatment of conservative groups," Hatch said. "Personal politics of IRS employees, such as Lois Lerner, also impacted how the IRS conducted its business."

Democrats mostly blamed management flaws at the tax-collecting agency and described a “dysfunctional culture” that opened the door and allowed agents to mistreat Tea Party and conservative groups that applied for tax-exempt status.

"Our investigation found that from 2010 to 2013, IRS management was delinquent in its responsibility to provide effective control, guidance, and direction over the processing of applications for tax-exempt status filed by Tea Party and other political advocacy organizations," the report, issued by the Senate Finance Committee, said.

Amid the scandal, the IRS didn't perform any audits of groups that might have been engaging in improper political activity from 2010 through April 2014, the report said. This was at a time when many high-profile tax-exempt groups were spending large sums of money on political activities.

The report also said managers were worried that selecting any of these groups for audits would give the impression that they were chosen because of their "political leanings."

Some groups ultimately waited as long as five years to have their applications processed, the report said.

The bipartisan report was issued along with separate – and conflicting- findings by Republican and Democratic investigators.

The investigators were unable to find common ground on whether anyone outside the IRS was involved in the scandal. They also failed to agree on whether liberal groups were mistreated by IRS representatives.

Both sides, however, agreed that the IRS remains unprepared to handle an onslaught of requests expected by non-profit groups interested in raising money for the 2016 election cycle.

The Associated Press contributed to this report.