The leaks from the grand jury investigating the police shooting of an unarmed 18-year-old in Ferguson, Mo., are not coming from the grand jurors themselves, officials said Thursday.
The St. Louis area is tensely awaiting the grand jury's decision, expected to be handed down in November, as to whether Ferguson Police Officer Darren Wilson should be criminally charged for fatally shooting Michael Brown on Aug. 9.
In recent weeks, local protesters and officials as prominent as U.S. Atty. Gen. Eric H. Holder Jr. have been incensed over leaked information appearing in media reports, including what witnesses said in front of the grand jury, whose workings are supposed to be confidential.
Those reports cited unnamed officials who had been briefed on the investigation. The details were largely favorable to Wilson's account of the shooting, prompting a strongly worded statement last week from the U.S. Justice Department that "there seems to be an inappropriate effort to influence public opinion about this case."
On Thursday, St. Louis County Prosecuting Atty. Robert P. McCulloch released his own statement asserting that "no information or evidence has been released by the grand jury" itself, adding that he nonetheless found the media leaks "exasperating."
McCulloch then addressed a tweet from early October that also stirred up activists, when a user under the handle @thesusannichols, criticizing demonstrators, tweeted, "I know someone sitting on the grand jury There isn't enough at this point to warrant an arrest. #Ferguson."
Susan Nichols, a St. Louis-area resident, immediately denied sending the tweet, saying that her account had been hacked, and officials vindicated her claim Thursday.
"An investigation revealed that the account had, indeed, been hacked and the origin/author of the tweet is unknown," McCulloch said Thursday. "The owner of the account has no connection with any member of the grand jury."
Nichols could not be reached for comment Thursday.
How the "hack" -- typically defined as an intrusion from an unauthorized user -- happened remains unclear.
A spokesman for McCulloch, Ed Magee, told the Los Angeles Times on Thursday that Nichols had fully cooperated with investigators checking for a possible grand jury leak and had provided her computer.
Magee said the hacking determination was made after a "forensic search" of Nichols' computer.
"It never came from her computer," Magee said. "We have to prove that something occurred, and we can't prove that it came from her."
But tweets can also come from phones. When asked how officials determined that Nichols' account -- which had posted tweets critical of the Ferguson protests and of the protests surrounding the George Zimmerman case a year earlier -- had been hacked, Magee said investigators had not gotten records from Twitter.
When investigators contacted Twitter to get more information about the tweet in question, Twitter officials told them "once a tweet has been deleted, it is no longer available on Twitter," Magee said. "The tweet in question was deleted before we could get a subpoena."
The tweet had been deleted almost immediately after it was posted, but at least one user captured it in a screenshot as other users pointed out that grand jury information is supposed to be secret.
According to Twitter's law enforcement guidelines, the service may only retain some user information, such as IP logs, for "a very brief period of time."
"Content deleted by account holders (e.g., tweets) is generally not available," Twitter's law-enforcement guidelines say.
Activists had previously criticized the prosecutor's office for its initial, shrugging reaction to last week's grand jury leaks from unnamed officials.
Magee said previously, "There's really nothing to investigate," as the leaks could have been coming from federal officials who are also investigating Brown's death and the Ferguson Police Department.
"We don't have control over anybody leaking anything," Magee said last week. "All we can control is people in our office and the grand jury, and it's not coming from us or the grand jury."