SAN FRANCISCO — A probe of grand jury leaks has developed into a criminal investigation to determine who gave a journalist for the Washington Times classified information about a Chinese espionage case.

A federal judge in Southern California, Cormac Carney, ordered the inquiry last year after finding evidence that prosecutors or investigators gave the newspaper’s national security reporter, William Gertz, information about the case against an engineer, Chi Mak, and his family.

In an order last week, Judge Carney said the Justice Department probe also is examining whether leaks about the case violated the Espionage Act. “The government has informed the court that the scope of its investigation is broader than determining whether a violation of rule 6(e) occurred. The government is also investigating possible violations of 18 U.S.C. § 793 (unlawful communication of classified information) arising from various publications in the media about this prosecution,” the judge wrote.

Judge Carney’s language suggested that the criminal inquiry involves disclosures beyond those contained in Mr. Gertz’s articles and a book he recently published, “Enemies: How America’s Foes Steal Our Vital Secrets — and How We Let It Happen.”

In October 2005, FBI agents arrested Chi Mak’s brother and sister-in-law, Tai Mak and Fuk Li, at Los Angeles International Airport as the couple prepared to board a flight to Hong Kong. Authorities said they were carrying an encrypted disk of propulsion designs Chi Mak obtained from his employer, Power Paragon.

The three were initially charged with failing to register as agents of China, but an article by Mr. Gertz predicted more serious charges in the case. Those charges, of conspiracy to export defense articles, were filed last fall, largely as the reporter suggested.

Prosecutors in California’s central district recused themselves from the leak probe, so it was assigned to the U.S. attorney’s office in Washington, the judge disclosed. A prosecutor in that office, Jay Bratt, has been investigating with agents from the FBI’s Washington field office.

The Espionage Act, passed in 1917, is one of the main statutes the government employs to prosecute leaks of classified information. The law has traditionally been used to prosecute spies, as well as government employees or contractors who release secret data.

However, the Justice Department has stirred heated debate by using the broadly worded statute to charge two pro-Israel lobbyists who allegedly passed on classified information to reporters and an Israeli diplomat.

Journalists’ groups have said the prosecution of the lobbyists, Steven Rosen and Keith Weissman, raises the specter that reporters could be charged simply for publishing classified information. Attorney General Alberto Gonzales has declined to rule out that possibility.

Judge Carney’s order did not indicate whether journalists were targets of the leak probe. A spokesman for Mr. Bratt’s office, Channing Phillips, said he would not comment on a pending investigation.

Mr. Gertz declined to comment for this article. Defense lawyers sought to subpoena the reporter to testify at a pre-trial hearing, but the judge rejected that request.

Jury selection in Chi Mak’s trial is set to begin next week in Santa Ana, Calif. He has pleaded not guilty and is set to stand trial separately from his relatives, whose trials are expected to follow.