U.S. Secret Service documents show that the agency played a key role in the investigation of free-information activist Aaron Swartz and watched his case closely until he committed suicide.

Swartz died in New York City in January as he faced trial on charges he hacked into a Massachusetts Institute of Technology archive of scholarly articles with the aim of making the information freely available.

The documents, released under the Freedom of Information Act, show the Secret Service field office in Boston secured documents and electronic devices seized during a search of Swartz's home and research office at Harvard University.

Agents also joined local police who interviewed Swartz's associates, including a San Francisco woman who told them that he called her and asked her to call his lawyer to arrange bail.

A co-founder of Reddit and activist who fought to make online content free to the public, his death prompted an outpouring of grief from prominent voices on the intersection of free speech and the Web.

Aaron Swartz, 26, hanged himself in his Brooklyn apartment weeks before he was to go on trial on accusations that he stole millions of journal articles from an electronic archive in an attempt to make them freely available. If convicted, he faced decades in prison and a fortune in fines.