Photo: Paul Chinn, The Chronicle Photo: Amy Osborne / Special To The Chronicle Photo: Paul Chinn / The Chronicle Photo: Paul Chinn / The Chronicle

Under fire for a raid on the home and office of a freelance journalist who refused to identify a confidential source, San Francisco Police Chief Bill Scott Tuesday explained the action by saying his department suspected the man took part in a criminal conspiracy to steal an internal police report on the February death of Public Defender Jeff Adachi.

“We believe the line was crossed,” Scott said. “We believe he took part in this act.”

But in an extraordinary news conference, Scott alleged only that the journalist, Bryan Carmody, participated in receiving and distributing a leaked government report — an action that is common in the media and protected by the First Amendment.

The chief explained why police believe Carmody participated in a conspiracy: “We believe that ... an SFPD employee was a part of this. We believe that in order for this to be successfully pulled off, there had to be some contact between the employee and Mr. Carmody ... we believe he was part of the effort to illegally obtain this report.”

Scott alternately said of the May 10 raid: “I’m not here to try to defend it.” He acknowledged that “leaks happen all the time” and that “I understand a journalist can receive reports.” He said repeatedly, “There are some lessons to be learned here.”

Asked about the new allegation on Tuesday, Carmody said, “I’m speechless.”

Photo: Bryan Carmody / Associated Press

He said he did not pay for the report or conspire to steal the report. “I received a copy of the thing,” he said.

Carmody said he obtained the police report from a confidential source shortly after Adachi’s death at age 59 on Feb. 22. He then sold it to three television news stations, who aired portions of it.

Some city officials were angered by the leak, suspecting it was an effort to smear the late public defender, who was known for his crusades against police misconduct.

Police served a search warrant on Carmody’s home and office, seizing computers, phones and other items in a bid to identify his source.

Scott said the police investigation is focused on SFPD employees and that “a secondary focus of this investigation is whether Mr. Carmody was an active participant in the commission of criminal acts, beyond his role with the news media.”

Possible crimes, police said, include conspiracy to commit a crime, theft, unlawful dissemination of a confidential report, and delaying or obstructing a public officer. Scott said Carmody’s motive would be profit, though Carmody has said he makes a living as a freelancer by selling videos and documents.

Photo: Paul Kuroda / Special To The Chronicle

The chief also noted that in an interview with investigators Carmody “expressed disdain for Mr. Adachi.”

California’s shield law protects journalists from being compelled to reveal their sources. The law specifically bars police from searching journalists in order to uncover a source. Asked about the shield law, Scott said, “We do believe Mr. Carmody committed a crime.”

Later, he said, “We respect the news media,” and promised his department would “really dissect (its investigation) and be thoughtful about it. We have to own what we own.”

“I hope this is not coming across as a defense,” he said. “This is an opportunity to tell people why we did what we did.”

Scott spoke after police officials said in court earlier in the day that they would return all property to Carmody. But while officials said they will give back computers, cameras, hard drives and other electronic equipment, it was not immediately clear what investigators planned to do with any evidence or information they had discovered and downloaded during and since the raid.

Attorneys for Carmody and the Police Department discussed the issue during a brief hearing in San Francisco Superior Court. Carmody’s lawyer, Thomas Burke, sought the return of his client’s property, while asking Judge Samuel Feng to quash the two search warrants police obtained before searching Carmody’s home and office.

Burke, who has represented The Chronicle and its parent company, Hearst Corp., in other cases, has argued that police violated his client’s right to due process along with the state shield law.

“I think it’s important when you have something like this happen you get the material back as soon as you can,” Burke said outside court. “But we want the search warrants revoked, and we want it made clear that they shouldn’t have been issued in the first place.”

Ronnie Wagner, an in-house attorney at the Police Department, did not file any motions opposing the effort to quash the warrants and did not provide any justification for the search during the hearing. Feng did not rule on any motions and set a deadline for police to file any opposition by May 31. Attorneys are due back in court June 10.

An attorney representing the First Amendment Coalition — a nonprofit that advocates for free speech and government accountability — filed a motion to unseal the search warrants in the case. The Police Department filed the warrants under seal, leaving it unclear precisely what officers disclosed in the affidavits describing their suspicion that a crime had occurred. Two judges, Victor Hwang and Gail Dekreon, signed the warrants but have not commented.

“This highlights the very serious need for the Police Department search warrant material to be unsealed,” said David Snyder, executive director of the First Amendment Coalition. “It’s one thing to have the police chief explain what happened at a press conference a week and a half later. It’s another thing entirely to understand what the Police Department told the judges that signed the warrant.”

The case has drawn national attention over concern that the search undermined press freedom, which depends heavily on journalists’ ability to protect confidential sources. A growing number of San Francisco officials, including some supervisors and District Attorney George Gascón, have criticized the raid.

Police showed up at Carmody’s Outer Richmond District home with a sledgehammer, drew their guns and cuffed him for more than six hours. Asked about the sledgehammer on Tuesday, Scott said, “We know that looks bad.”

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky