Two PBS documentaries, "Nova" and "Frontline," take a turn down criminal paths tonight, while two network miniseries, "The Invaders" and "Streets of Laredo," conclude on Fox and CBS.
* "Nova: Hunt for the Serial Arsonist" (8 p.m.-9 p.m., MPT, Channels 22, 67) -- The science of crime-scene investigation is scrutinized through the solving of a 1991 rash of arson fires at Los Angeles stores. PBS.
* "The Invaders" (8 p.m.-10 p.m., WBFF, Channel 45) -- In the original series (1967-68), Roy Thinnes never had much luck persuading people that aliens had invaded the Earth. Will Scott Bakula have any better luck in tonight's miniseries conclusion? Fox.
* "Home Improvement" (9 p.m.-9:30 p.m., WMAR, Channel 2) -- He demonstrates all the skills on his TV show, so why does Tim's (Tim Allen) effort to build his son a room turn into a disaster? ABC.
* "Frontline: Natasha and the Wolf" (9 p.m.-10:30 pm., MPT, Channels 22, 67) -- Cloak and dagger stories happened behind the Iron Curtain, too, as the documentary series focuses on the case of a high-ranking female prosecutor who fell for a Soviet state criminal. PBS.
* "Streets of Laredo" (9 p.m.-11 p.m., WJZ, Channel 13) -- The miniseries based on author Larry McMurtry's "Lonesome Dove" sequel concludes as Call (James Garner) closes in on Garza (Alexis Cruz, and Lorena (Sissy Spacek) hopes Pea Eye (Sam Shepard) will come home. CBS.
* "Fields of Fire: Sports in the '60s" -- (10 p.m.-11 p.m., HBO) -- Singer-songwriter Richie Havens narrates this new documentary that tracks the rise of sports superstars, including Kareem Abdul-Jabbar, Jim Brown, Joe Namath, Billie Jean King and many others. Also included are graphics by artist Peter Max.