It doesn't take much detective work to figure out why TNT wants to keep "The Closer" on for another year.

The cable network has renewed the series, the most popular show on ad-supported cable, for a fourth season. Deputy Chief Brenda Leigh Johnson (Kyra Sedgwick) and her team will be back on the case in the summer of 2008 with 15 new episodes.

"With each season, 'The Closer' keeps getting better while its audience keeps getting bigger," says Michael Wright, head of programming at TNT. "From its consistently excellent execution to its unprecedented popularity, including among young adults who are recording it in large numbers, it is constantly proving itself to be one of television's biggest success stories."

"The Closer" is drawing 7.75 million viewers a week this season, an improvement of better than a million viewers over last season's 6.65-million average. About 1.2 million of those people are watching the show on their DVRs, TNT says, making it the most-recorded drama among viewers and the adults 18-49 and 25-54 demographics TNT cares about most.

Sedgwick earned her second Emmy nomination this year for playing the neurotic, cunning and razor-sharp Johnson. She also won a Golden Globe for her performance earlier this year.