Swartz had been facing charges for hacking into the Massachusetts Institute of Technology's JSTOR archive system and downloading more than 4 million items he planned to distribute free on file-sharing websites.
He was found hanged in his apartment in New York's Brooklyn borough Friday.
A document filed in U.S. District Court officially dropped the charges against him, The Boston Globe reported.
The action came after the hacking group Anonymous took credit for posting messages to MIT websites calling for an overhaul of computer-crime laws.
Anonymous hackers said they posted tributes to RSS co-founder Swartz, 26, an outspoken advocate of open information in a legal battle over digital copyright, The Washington Post reported.
Besides being involved in the technology behind RSS, which alerts users to real-time updates on websites, Swartz had an early role at Reddit and founded the advocacy group Demand Progress.
He believed the articles on JSTOR should be more widely available, the Post said. He hacked into the database's systems and downloaded articles using a computer hidden in a closet at MIT.
Swartz was charged with felony hacking and his trial was to begin this spring.
In the messages Sunday, Anonymous called for an overhaul of intellectual property and computer crime laws and said Swartz's death should wake up Internet freedom advocates.
"We call for this tragedy to be a basis for a renewed and unwavering commitment to a free and unfettered Internet, spared from censorship with equality of access and franchise for all," the group said.
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