"Homicide" is back! But tonight also marks a notable departure, as anchor Robert MacNeil retires from the nightly PBS news desk. Baltimore's Alan Keyes is also profiled in a new series looking at the 1996 presidential hopefuls.
* "MacNeil/Lehrer NewsHour" (6 p.m.-7 p.m., MPT, Channels 22, 67) -- Title namesake Robert MacNeil makes his last appearance, and a nostalgic special edition marks his departure -- as well as the 20th anniversary of the program. Next week, the show becomes merely "The NewsHour with Jim Lehrer." PBS.
* "Unsolved Mysteries" (8 p.m.-9 p.m., WBAL, Channel 11) -- Here's a mystery worth exploring: How did this reality-based re-enactment show make it to an eighth season? Actor Brandon Lee's tragic movie-set death in 1993 -- he was killed by a blank pistol -- helps launch the new season. Robert Stack returns as host. NBC.
* "The Challengers '96" (9 p.m.-10 p.m., MPT, Channels 22, 67) -- Alan Keyes, the former U.S. Senate candidate in Maryland and local radio talk-show host, is among the first presidential candidates profiled by Ken Bode, host of "Washington Week in Review," in this four-week series. Also up tonight: Tennessee Gov. Lamar Alexander. PBS.
* "Picket Fences" (9 p.m.-10 p.m., WJZ, Channel 13) -- Well, it could happen to anybody, couldn't it? A simple case of mistaken identity? Max (Lauren Holly) is slapped with a suspension for shooting a man dressed as a bratwurst. In another plot line, Kimberly (Holly Marie Combs) may be pregnant. CBS.
* "Homicide: Life on the Street" (10 p.m.-11 p.m., WBAL, Channel 11) -- Ned Beatty and Daniel Baldwin have left the show, but Reed Diamond joins the cast as Det. Mike Kellerman, in the two-part series premiere of the police drama filmed in Baltimore. (Part 2 airs next week.) NBC.
* "Investigative Reports: Wife Beaters" (9 p.m.-10 p.m., A&E; Network) -- In light of the spouse-abuse issue raised in the O. J. Simpson case, the series examines domestic violence in the United States, including efforts by women judges to speed the handling of such cases.
* "Rivals! Martin Luther King and George Wallace" (10 p.m.-11 p.m., The Discovery Channel) -- In the week of the Million Man March in Washington, a timely edition studies the racial polarization of the 1960s, as symbolized by the civil rights leader and the Alabama governor, who was subsequently crippled by an assassination attempt in Laurel.