With Barry Bonds still in their sights, federal investigators can now use the names and urine samples of about 100 Major League Baseball players in their steroids probe, following a ruling Wednesday from a federal appeals court.

The 2-1 decision by the 9th U.S. Circuit Court of Appeals overturned three lower court decisions and could help authorities pinpoint the source of steroids in baseball. It could also bolster the perjury case against the star outfielder, who is under investigation for telling a grand jury he never knowingly used performance-enhancing drugs.

Investigators seized computer files containing the test results in 2004 during raids of labs involved in MLB's testing program. The samples were collected at baseball's direction the previous year as part of a survey to gauge the prevalence of steroid use. Players and owners agreed in their labor contract that the results would be confidential, and each player was assigned a code number to be matched with his name.

Quest Diagnostics of Teterboro, N.J., one of the largest drug-testing firms in the nation, analyzed more than 1,400 urine samples from players that season. Comprehensive Drug Testing of Long Beach, Calif., coordinated the collection of specimens and compiled the data.

Armed with data from both labs, government officials now can match the positive test samples with the players' names. Those players then could be called before a grand jury and asked how they obtained their steroids. If enough testify that they got the drugs from Bonds' personal trainer, Greg Anderson, it could undermine Bonds' claim that he didn't know Anderson was supplying him with illegal substances.

Anderson is currently in prison for refusing to testify in the perjury probe. He was previously convicted of steroids distribution.

Bonds' lawyer questioned why the government continues to pursue Bonds when he doesn't believe the Giants' outfielder was among those who tested positive in 2003.

"If Barry is one of the players that did not test positive in '03 for steroids, I would hope that it would cause the government to rethink their continuing harassment they've engaged in for years," attorney Michael Rains said.

U.S. Attorney Kevin V. Ryan of San Francisco said the office is reviewing the decision "to determine what the next investigative step may be."

Bonds has always maintained he never tested positive for illegal drug use. However, federal investigators demanded to see the 2003 test results for Bonds, Gary Sheffield, who was recently traded by the New York Yankees, the Yankees' Jason Giambi, and seven other players.

When they raided the testing labs for those 10 results, investigators also seized computer files containing the test results of nearly 100 other players not named in the government's subpoena and warrants.

Bonds' attorney, Michael Rains, didn't return phone calls for comment.

The testing was part of baseball's effort to determine whether a stricter drug-testing policy was needed. Because 5 percent or more of the tests for steroids came back positive, it automatically triggered the start of testing with penalties in 2004.

Subpoenas were issued to Quest and CDT in late 2003, a day before the test results were to be destroyed, and in April 2004 Internal Revenue Service agents seized the results and samples. It's unclear whether the seized data includes test results or specimens from Bonds.

The players' union sued to keep the government from accessing the records, saying the seizures violated the players' constitutional rights.

The 120-page decision from the appellate panel rejects that claim, and overturns decisions by U.S. District Judges Florence-Marie Cooper in Los Angeles, Susan Illston in San Francisco and James Mahan in Las Vegas.

The key opinion, which says federal prosecutors are entitled to the urine samples and names of those who tested positive, overturns a ruling by Illston, who sided with the players' union and quashed the subpoenas, saying they constituted harassment and were unreasonable.

"The district court rested its order on legally insufficient grounds, and abused its discretion in granting the motion to quash," Judge Diarmuid F. O'Scannlain wrote for the appeals court.

In dissent, Judge Sidney R. Thomas voted to uphold Illston, writing that the government's action "suggests an abuse of grand jury process."

The players' union can now ask for a new hearing before the full 9th Circuit or appeal the panel's ruling to the U.S. Supreme Court.

The union's general counsel, Michael Weiner, declined to immediately comment, saying he wanted to first review the decision.

Separately, the court also ruled that "the government's seizures were reasonable under the Fourth Amendment" and sent the case back to the district court to review what evidence can be used and what must be returned.

Circuit Judge Richard C. Tallman also heard the appeal.

In dissenting from much of the majority opinion, Thomas wrote: "It's a seizure beyond what was authorized by the search warrant, therefore it violates the Fourth Amendment.

"The scope of the majority's new holding could not be greater; it removes confidential electronic records from the protections of the Fourth Amendment. ...

"Perhaps baseball has become consumed by a 'Game of Shadows,"' Thomas added, referring to the book by two San Francisco Chronicle reporters, "but that is no reason for the government to engage in a 'Prosecution of Shadows.' "

The government's investigation of the Bay Area Laboratory Co-Operative, a now-defunct Burlingame supplements lab at the center of the steroid scandal, already has resulted in guilty pleas from BALCO president Victor Conte, Bonds' personal trainer Anderson, BALCO vice president James Valente, chemist Patrick Arnold and track coach Remi Korchemny.

The case is United States v. Comprehensive Drug Testing Inc., 05-10067.