WASHINGTON - Two Secret Service agents suspected of driving under the influence and striking a White House security barricade disrupted an active bomb investigation and may have driven over the suspicious package itself, according to current and former government officials familiar with the incident.

These and other new details about the March 4 incident emerged Thursday from interviews and police records obtained by the Washington Post.

The episode has prompted questions from lawmakers about whether the newly appointed leaders of the Secret Service are capable of turning around the troubled agency. Among the lawmakers' questions: Whether a Secret Service supervisor, as witnesses have alleged, ordered officers to let the agents go home without facing sobriety testing.

An investigation by the Department of Homeland Security's inspector general is centering on the possible misconduct of two senior agents, including a top supervisor on President Obama's protective detail.

The incident unfolded on a hectic night for Secret Service officers guarding the White House. About 10:25 p.m., a Pennsylvania woman hopped out of her blue Toyota near the southeast entrance of the White House and, holding a package wrapped in a green shirt, approached an agent.

"I'm holding a [expletive] bomb," she yelled, according to a government official with knowledge of the incident.

The woman then put the object on the ground and retreated to her car, the official said. The agent ran to the car and opened the front passenger door and ordered the woman to get out. But she put the car in reverse and accelerated, striking the agent with the open door. The agent reached inside the car and forced it into park, said the government official, but the woman was able to shift it back into drive and drive forward, again hitting the agent and forcing him to jump out of the way.

The woman then sped off.

Police secured the area with tape and called an explosives inspection team to check the package for potential explosive materials or other dangers.

But shortly before 11 p.m., the two high-ranking Secret Service agents, returning from a work party about eight blocks from the White House, drove their government car through the crime scene. According to people familiar with the incident, they drove through police tape and then hit a temporary barricade, using the car to push aside some barrels. An agency official said Thursday that the car was not damaged.

The episode was caught on surveillance video. Investigators who have reviewed the tape say the pair either drove very close to or over the suspicious item wrapped in the shirt, one law enforcement official said.

Secret Service officers on duty considered the agents' behavior to be erratic and suspected they were drunk, according to current and former officials familiar with the incident. The officers wanted to arrest the agents - but a more senior supervisor at the complex told them to let the agents go, the officials said.

Meanwhile, at 11:45 p.m. the police explosives team determined the suspicious item was not a threat. The item was a book.

Secret Service officers found the woman two days later to question her about her threats on the White House. A government official said that she has had contact with the Secret Service in the past, and that the agency had her photo on file.

On Thursday, a government official said a warrant for the woman's arrest had been issued through a D.C. court, charging her with assault with a dangerous weapon, the car.

The Secret Service agents under investigation are Mark Connolly, the second-in-command on Obama's detail, and George Ogilvie, a senior supervisor in the Washington field office.

Through a Secret Service spokesman, Connolly and Ogilvie declined to comment.

An agency official said the two employees had been moved to "non-supervisory, non-operational assignments."

The incident has presented an early test for Secret Service Director Joseph Clancy, who was appointed last month by Obama after a string of agency missteps and security lapses.

While declining to discuss the investigation, Obama's aides described Clancy as the right man to fix problems.

"Nobody has higher standards for the Secret Service than Director Clancy," said White House spokesman Eric Schultz.

Yet lawmakers charged with overseeing the agency were aghast and wondered how - after intense national scrutiny and a rotating cast of directors - the Secret Service still hasn't corrected problems involving behavior of its agents. In a rare move, the top Republican and Democrat on the House's oversight panel joined forces to say that while many of the agency's top leaders have been replaced, "this incident begs the question of whether that is enough."

"Clearly this incident is a major wake-up call," the Democrat, Rep. Elijah Cummings of Maryland, said later in an interview.

On Thursday, Rep. Jason Chaffetz (R., Utah), chairman of the House Oversight and Government Reform Committee, said he was concerned that the events of March 4 suggest some in the Secret Service feel they are above the law.

"The director needs to send a message. He needs to signal there is going to be new accountability in the agency," Chaffetz said. "We're still learning all the facts, but I'm still not very impressed by how this is going."

A spokesman for Obama said aboard Air Force One that the president retains full confidence in Clancy.