The worm did not spread to many computers when it appeared last week, but attracted attention because of the gimmick it used to trick readers into launching the attachment, promising "pictures taken by one of the U.S. spy satellites during one of its missions over Iraq" and other war-related files.
However, the worm's code also contained an unsubtle message that police said helped them track down their suspect: "Coded by Uncle Roger in Haernoesand, Sweden, 03.03. I am being discriminated by the Swedish school system. This is a response to eight long years of discrimination. I support animal-liberators worldwide."
The suspect was found in Haernoesand, a town about 250 miles north of Stockholm, police spokesman Torbjoern Ull told Swedish newspapers on Tuesday. Police raided the suspect's home on Friday, and police said the suspect later confessed to creating Ganda. The case is Sweden's first involving a virus writer.
The man was not arrested but will be charged with computer trespassing and inflicting damage, according to daily newspaper Aftonbladet.
Attackers commonly use "social engineering" tactics to lure computer users into danger. The, one of the most destructive ever, posed as a romantic message.
ZDNet U.K.'s Matt Broersma reported from London. Silicon.com's Will Sturgeon contributed to this report.