Documentaries by Asian adoptees searching for their roots have become a genre unto themselves, but this feature by Kim-Chi Tyler (2000, 72 min.) is one of the best I’ve ever seen. Utterly frank, Tyler confronts her bedridden American stepfather with questions about her Vietnamese mother, and after returning to the village she left in the early 1970s, she interrogates various relatives about her mother’s divorce from her biological father, still a source of rancor between the families. At the center of the mystery lies a missing child: one side insists that the marriage produced three children (including Kim-Chi and her brother, who eventually emigrated to the U.S. with their mother and their elderly stepfather), while the other family claims there were four. The story itself is totally absorbing, a heart-wrenching footnote to the tangled history of the Vietnam War, but what sets the film apart from others like it is the unpleasant self-portrait of a woman bullying her way toward a secret better left concealed. On the same program: Sea in the Blood (2000, 26 min.), an experimental video in which the gay Canadian artist Richard Fung connects his sister’s death from thalassemia with his partner’s battle against AIDS, crafting an ingenious montage of home-movie clips, printed and spoken words, and images of the two lovers sinuously submerged in water. Gene Siskel Film Center, Thursday, April 19, 6 PM. –Ted Shen