A woman pleaded guilty to conspiracy to tamper with evidence after being accused with her husband and former DuPont employees of stealing and selling trade secrets to China for a highly coveted whitener used in cars, Oreo cookies and a variety of other products.

The plea on Tuesday was part of an agreement with federal prosecutors that calls for Christina Liew to serve probation, no prison time, and pay up to $6 million in restitution, her attorney Doron Weinberg said.

"We are very much relieved and gratified that the case has been resolved at least by the parties on a basis that will not involve incarceration," Weinberg said.

A judge must still accept the terms of the agreement and decide a final restitution value. Liew is scheduled to be sentenced in September.

Authorities say Walter and Christina Liew started a small company in the 1990s to take advantage of China's desire for the white pigment known as titanium dioxide and paid retired DuPont employees thousands of dollars for sensitive company documents about how to make it.

The pigment represents a multi-billion-dollar industry, with DuPont controlling about 20 percent of the market.

The Liews were accused of selling the secrets to a DuPont competitor controlled by the Chinese government, which was importing much of its titanium dioxide from the West and was hungry to produce more domestically.

Walter Liew was sentenced to 15 years in prison last year and fined $28 million after a jury convicted him of economic espionage.

The same jury also found Robert Maegerle, a former DuPont employee accused of joining the Liews, guilty of economic espionage. He was sentenced to 2 and ½ years in prison.

Tze Chao, another former DuPont scientist who worked with the Liews, pleaded guilty in 2012 to conspiracy to commit economic espionage.

The charge to which Christina Liew pleaded guilty stemmed from allegations that she lied to the FBI about a key to a safe-deposit box during a raid on the couple's home in Orinda, a suburb about 20 miles east of San Francisco.

At her husband's direction, she denied any knowledge of the key, according to court documents.

Agents then followed Christina Liew to an Oakland bank that contained the box. It contained incriminating documents, according to prosecutors.

Weinberg said Christina Liew had a lesser role in the events that led to the indictment and has responsibility for the couple's 14-year-old child.