“Law & Order” (9 p.m., NBC) turns to a sad, true and familiar story for one of its “ripped from the headlines” plots. Tonight’s episode involves the death of an actress found hanging in her office. Although her death looks like a suicide, detectives discover quickly that she was actually killed by a blow to the head and that the “hanging” was staged to throw the police off the track. After police investigate possible suspects linked to her acting career, they settle on a construction worker with whom she had quarreled only days before her death.

The story closely resembles the true account of the November murder of actress Adrienne Shelly, who was found hanging in the shower of her Greenwich Village, N.Y., apartment. A construction worker has been arrested in that case.

Shelly had made her reputation in the independent-film world, first appearing in films by director Hal Hartley, including “The Unbelievable Truth” and “Trust.” She was most recently seen in the film “Factotum,” starring Matt Dillon.

“Waitress,” a movie written and directed by and starring Shelly along with Keri Russell (“Felicity”) and Cheryl Hines (“Curb Your Enthusiasm”), was screened posthumously at the Sundance Film Festival.

In addition to her film work, Shelly appeared in episodes of “Oz” and “Homicide: Life on the Street,” and in 2000 she was featured in an episode of “Law & Order.”

¢ Tens of millions watch “American Idol.” But what would it be like to win? The Canadian-produced series “Instant Star” (7:30 p.m., The N) follows the fortunes of teenage talent-show winner Jude (Alexz Johnson). Beginning its third season tonight, “Star” follows Jude as her musical reputation shifts from teen prodigy to established talent. Every episode of “Instant” features a new song.

Tonight’s other highlights

¢ Melinda shares a basement with an apparition with knowledge of a recent jewel heist on “Ghost Whisperer” (7 p.m., CBS).

¢ Annabeth prosecutes a woman accused of putting a hit on her hired surrogate mother on “Close to Home” (8 p.m., CBS).

¢ A stranger claiming to be a leper hires Adrian for a private job on “Monk” (8 p.m., USA).

¢ Sam’s ex-lover wakes up from a 20-year-coma on “Las Vegas” (8 p.m., NBC). Sandra Bernhard guest stars as a housekeeper Ed is keen to replace.

¢ A 32-year-old professional woman clings to a coat she has worn since she was a college student on “What Not to Wear” (8 p.m., TLC).

¢ “Ms Adventure” (8 p.m., Animal Planet) examines long-term mating habits in the animal kingdom.

¢ A repeat “Chappelle’s Show” (8:30 p.m., Comedy Central) features a spoof documentary expose of racism amongst Hollywood’s animal stars.

¢ A martial artist’s murder doesn’t add up on “Numb3rs” (9 p.m., CBS). Guest star Tito Ortiz doesn’t need much introduction to the world of extreme martial arts. He’s the former light-heavyweight Ultimate Fighting champion.

¢ Scheduled on “20/20” (9 p.m., ABC): broken promises.

¢ Evidence points to murder after a tennis star vanishes on “Psych” (9 p.m., USA).

¢ “Real Time with Bill Maher” (10 p.m., HBO) kicks off its fifth season.