An internal L.A. County Sheriff's Department email obtained by The Times raises new questions about the role former Undersheriff Paul Tanaka played in the handling of a jail inmate who was working as an FBI informant.

Federal prosecutors allege that seven current and former deputies took part in a conspiracy to hinder the FBI by, in part, hiding Anthony Brown within the jail system after they learned he was an informant. Brown was secretly providing information to the FBI about deputies suspected of being corrupt or abusive.

Tanaka, who is now running for sheriff, has not been accused of any wrongdoing by federal officials.

The email, written while Brown was allegedly being hidden from the FBI, states that Tanaka or one of his subordinates had to be present before deputies could move Brown.

In the email, Deputy Gerard Smith warns his colleagues: "To keep yourself free of any controversy … let the approved, above listed people deal with Browns issues… It has been expressed to me (several times now) that this is one of the most important investigations involving The Los Angeles County Sheriff's Department in its 160 year history. No joke."

Tanaka said in a statement to The Times that he had a minimal role in the Brown matter — known inside the department as "Operation Pandora's Box" — and that he did nothing improper or illegal. He also said he does not recall being made aware of the contents of the email before it was sent.

"While I was involved in some aspects of the implementation of these orders, I was not involved in or had knowledge of other aspects and my name was sometimes used without my knowledge or consent because of my position," he said in the statement.

The operation to closely monitor Brown began in 2011 after sheriff's officials learned that he was secretly working as an informant in an FBI investigation of corruption and abuse within the jails. Deputies discovered that Brown was using a smuggled cellphone to communicate with his FBI handler on the outside.

After sheriff's officials got wind of Brown's cooperation with the FBI, officials allegedly took part in a conspiracy to hinder the FBI. According to federal prosecutors, they hid Brown rather than turn him over to federal authorities, who had obtained a court order for him to appear before a grand jury to testify about misconduct by jailers.

Brown's name on custody records was allegedly changed, and he was moved out of the jail to a distant holding cell. Sheriff's employees were told not to allow federal agents to have contact with him, according to an indictment unsealed in December.

Of the current and former sheriff's employees facing charges, the highest ranking is a lieutenant. But sheriff's officials involved have alleged that the handling of the Brown case went all the way up to former Sheriff Lee Baca, who retired in January, and his top aide, Tanaka.

Baca has downplayed his involvement, and a department spokesman has said the goal of moving Brown around was to protect him from deputies seeking revenge, not to hide him from the FBI. Baca has said he had been assured he is not a target of the probe.

Tanaka has maintained that his role in the Brown case was minimal and that it was being led by Baca.

In the email, which was not sent to Tanaka, Smith assigns deputies from the jailhouse intelligence unit, Operation Safe Jails, to watch over Brown around-the-clock. Smith tells them who needs to be present if Brown is to be moved.

"If you are getting this Email, you have been signed up to work this very important detail. I am in charge of security and scheduling for this detail. Please don't let me or the unit down. I have covered the background regarding Anthony Brown … the inmate we are tasked with protecting," his email reads. "For clarification his cell door (8225) will not be opened, without the 2 [Operation Safe Jails] Deputies who are assigned to be posted. If you get a pass for any movement, other than medical, call me for approval. Use your common sense. There will be no other movement, without the presence of the following people: US Tanaka, ICIB Cpt. Tom Carey, ICIB LT. Leavins, LT. G. Thompson, Dep. G. Smith or Dep. M. Manzo."

Smith's attorney declined to comment about the email.

Tanaka said he has been interviewed by the FBI and has testified before the grand jury about the handling of Brown.

He said in his statement that Baca made "two broad directives" regarding Brown's handling and the smuggled cellphone, "both of which were direct orders and, to my knowledge, were made in good faith and were not illegal."

Tanaka did not elaborate about what those orders were, but in the past he told The Times that Baca had ordered subordinates to keep the inmate from the FBI until the department finished with him, as well as explicitly denying a request from a federal official to return the smuggled phone Brown was using to talk to the FBI.

Tanaka said he could not elaborate further because he has been told he will be subpoenaed as a witness in the upcoming obstruction trial.

Last year, Tanaka was pushed to step down by Baca amid allegations that Tanaka encouraged overly aggressive policing, prized loyalty over merit and mismanaged sheriff's resources. Soon after, Tanaka announced he was running to replace his old boss.

robert.faturechi@latimes.com