Wired has raised further concern about a security researcher who disappeared.

A well-known security researcher and cybercrime foe appears to have gone missing in Bulgaria and is feared harmed, according to a news organization that hosts a blog the researcher co-writes.

Bulgarian researcher Dancho Danchev, who writes for ZDNet’s Zero Day blog, is an independent security consultant who’s garnered the enmity of cybercriminals for his work tracking and exposing their malicious activity. He has often provided insightful analysis of East European criminal activity and online scams.

His last Twitter update was October 20th, 2010, and hislast blog entry was September 11th, 2010.

A big clue in the case is that Danchev supposedly sent an “insurance” letter with photos to a friend before he disappeared. The letter accuses the Bulgarian government of monitoring him. The wiring in the photos, however, are exposed and easy to see; it does not look like professional surveillance work, which I would suspect Danchev also knew.