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A Texas grand jury has decided that a GIF can be just as deadly as a gun or knife.

The U.S Department of Justice and a Dallas grand jury issued indictments Monday against John Rayne Rivello, who is accused of intentionally tweeting a Graphic Interchange Format (GIF) animation designed to Newsweek journalist Kurt Eichenwald in order to provoke an epileptic seizure.

The grand jury's indictment refers to the GIF as "a deadly weapon," along with a tweet, an "electronic device," and Rivello's hands.

Eichenwald, who has epilepsy, said the tweet Rivello sent him in December caused him to have a seizure.

Writer Kurt Eichenwald attends The Informant! New York premiere at the Ziegfeld Theatre on Sept. 15, 2009 in New York City. Jim Spellman / WireImage

FBI investigators obtained a search warrant for Rivello's account, in which he allegedly posed under the name Ari Goldstein and used the handle @jew_goldstein, and said they found a series of direct messages that made Rivello's intentions clear.

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According to the DOJ complaint against Rivello, he sent messages to his friends after tweeting the seizure-inducing GIF to Eichenwald. One of the messages read, "I hope this sends him into a seizure." Another read, "Spammed this at [Eichenwald] let's see if he dies."

Experts in tech and cyberharassment law said it is likely the first time that a GIF has been deemed a deadly weapon used in a physical assault.

"I’m unaware of anybody being criminally prosecuted for this," defense attorney Tor Ekeland, who represents clients accused of federal cyber crimes, told NBC News. "If it’s not the first time, it’s one of the first times this has happened."

Ekeland, who is not involved in the case, noted that Rivello is being charged with a federal cyberstalking law that is frequently the subject of criticism from First Amendment advocates. The law criminalizes using electronic communication "with the intent to kill, injure, harass, [or] intimidate" a victim, but it's typically used in relation to images (like revenge porn) or speech (like emailed death threats).

What's likely unprecedented about this case is that Rivello's tweeted GIF is considered an assault weapon.

"Here they’re saying you used the internet as a weapon that causes physical harm," said Ekeland. "You’re in different territory, because that’s at least something you can have concrete testimony and evidence of, rather than squishy emotions and ‘Gee, I felt bad.’"

But Ekeland would still use a First Amendment defense, were it his own case: rulings on extreme cases can always be stretched and applied later in surprising ways.

"How do you know a photo can or can’t set off a medical condition? You can see the slippery slope here," Ekeland said. "Are they going to use it to ban art people don’t like because it upsets someone?"

University of Maryland cybersecurity expert Danielle Citron disagreed with the concern that the Eichenwald attack could be conflated with free speech.

“This doesn’t even get in the door of the First Amendment,” Citron told the Washington Post on Sunday. “It doesn’t have expressive value. . . . It doesn’t express someone’s autonomy of views and opinions. It’s not contributing to the marketplace of ideas.”

Citron cited the connectivity of medical devices as an example, wondering whether someone hacking into an insulin pump and using it to kill a diabetic could ever be construed as an act of free speech.

A case similar to Rivello's took place in 2008, when unknown hackers attacked the website for the Epilepsy Foundation and caused users to erupt in seizures. The hackers uploaded photosensitive flashing animations that resembled the one Rivello allegedly used to trigger a seizure in Eichenwald.