https://www.theguardian.com/us-news/2019/may/13/navy-seals-lawyers-received-emails-embedded-with-tracking-software

The tracking software was discovered almost immediately by defense lawyers who noticed an unusual logo of an American flag with a bald eagle perched on the scales of justice beneath the signature of Czaplak. It was not an official government logo.

Parlatore said suspicious tracking software was embedded in the logo. He contacted Czaplak to make sure his email had not been hacked.

“I can’t imagine you’d be trying to track defense attorneys’ emails,” Parlatore said he told Czaplak. “I want to make sure your system hasn’t been compromised.”

He said Czaplak told him he would check on it. Two days later, during a closed-door meeting with the judge in San Diego, the defense pushed for more answers and the prosecutor acknowledged sending something as part of an investigation, but declined to elaborate, Parlatore said.