and by the frontline journalism fund, with major support from jon and jo ann hagler, and additional supportm koo and patricia yuen, committed to bridging cultural differences in our communities... and from the fredric j. ridel living trust. (mouse clicks) >> narrator: it started on the online chat platform discord-- a post by a person known only as "lucca." (mouse clicking, computer pings) classified u.s. intelligence documents, one batch after another. (clicking, pinging) documents labeled "top secret" soon spilled onto social media. that's when it made headlines. >> top secret documents about the war in ukraine >> investigations are underway into the leak have appeared on social media. of classified pentagon documents. >> the pentagon is dealing with the fallout from the worst leak of u.s. national security intelligence in many years. >> top secret documents show ukraine's air defense vulnerability. >> after this hit the news, we're trying to figure out a: the extent of the leak; and b: obviously, who leaked it. ♪ ♪ (computer pinging) we were looking into lucca, trying to find traces of h