The U.S. Attorney’s Office is fighting to keep the names of those involved in the federal prosecution against Internet activist Aaron Swartz under court seal, arguing prosecutors have been victims of hacking and death threats.

Threatening emails have been sent to U.S. Attorney Carmen Ortiz and prosecutor Stephen Heymann, according to court documents, which said Heymann’s Facebook account was hacked and Heymann’s father, a Harvard professor, received a postcard with his photo in a guillotine.

“Our argument against it is that not only does it have an effect on the people involved in the case, but there’s also sometimes a residual effect,” said U.S. Attorney’s Office spokeswoman Christina Sterling.

The case against Swartz for illegally downloading academic articles he intended to publish for free online ended with his January suicide, but his lawyers are now asking the courts to release evidence ahead of congressional hearings on the case, which has been a rallying point for people with complaints of overzealous prosecution.

Swartz’s lawyers and prosecutors agree to redact personal information, such as email addresses and phone numbers from the court documents, but prosecutors and MIT have filed their opposition to releasing the names of those involved in the case, citing recent hacking and threats.