Prosecutors associated with the case against the late Aaron Swartz have received "harassing and threatening communications", including postcards of disembodied heads pictured next to guillotines.

Government lawyers have detailed the harassment in a court filing urging the court to keep details of the case redacted to protect individuals involved in the prosecution of the internet activist.

The Justice Department said that US attorney Carmen Ortiz and people connected to her office had been threatened on a number of occasions. Protestors demonstrated outside Ortiz' home. Assistant US attorney Stephen Heymann, the lead prosecutor on the case, had personal information - his email address, his phone number and the names of family members and friends - published online.

Heymann also received a postcard at home that had Ortiz's photo on one side and on the other side, a photo of a guillotine with a disembodied head that appeared to be that of MIT's President, along with a well-known symbol for hacktivist collective Anonymous in the corner.

Heymann's father, Philip, a professor at Harvard Law School who was unconnected with the case, also received a similar postcard with his own head next to the guillotine.

Swartz's estate lawyer has filed a request with the court for more information about the case to be made public following the hacktivist's suicide in January. The case against Swartz, alleging computer fraud after he copied millions of scientific articles from the nonprofit journal archive JSTOR to redistribute online, has been widely blamed for contributing to his death.

Both the US government and MIT, through whose systems Swartz ran the custom Python script to download the articles, have asked the court to keep anyone who doesn't want their name made public redacted from legal documents.

"The United States does not think it is appropriate to expose other people, particularly those who did not voluntarily inject themselves into this matter, to threats and harassment of this type under the circumstances here," the DoJ's filing said.

"The risk - which is both specific and credible - is simply too great to justify publishing the documents with the individuals’ names to Congress and the public."

MIT said that since Swartz's death, it had been "subject to threats to personal safety and breaches to its computer network".

"Despite these threats and breaches, MIT values openness and in fact intends to release a report of its involvement in the Swartz case, along with redacted documents," it said in its filing.

"Such openness, however, must take into account and address the potential for significant harm to individuals and MIT's network. Therefore, MIT opposes any modification of the Protective Order that does not contain provisions for the redaction of all identifying information of any member of the MIT community as well as… to protect any MIT network vulnerabilities."

Swartz has become a symbol for the concern around the Computer Fraud and Abuse Act and the punishments sought for hacking, whether for criminal or so-called hacktivist purposes.

The House Oversight Committee is currently investigating how his case was handled and whether an "appropriate level" of punishment was sought.

Swartz's lawyers have filed an official complaint with the DoJ alleging professional misconduct by Heymann including suppressing evidence and abusing plea-bargaining and sentencing guidelines. ®