Whatever Happened To Nick Yemana?

It happened in season 3 episode 11 of Barney Miller. A tray of brownies was sent to the detectives of the 12th by Wojo's girlfriend. What could go wrong, right? Let's examine. It was a highpoint for Sgt. Nick Yemana, played by Jack Soo, whose disappearance from the series was never explained. 

While yemana's absence from the show was never directly addressed, there were some hints. He was said to be at the DA's office, in court, or on vacation. But later we are led to believe he has passed away by these instances in the show.

In the last episode Barney remembers the detectives who were no longer there: Chano, Fish, Wentworth, and they show an old scene for each one. When he remembers Nick he looks like he is about to start crying, which would indeed indicate that Nick must have died, although exactly when is left up to your imagination. Also, since he has a broad smile when he remembers the others you can assume that Fish and the others are all still alive at that point.

In reality, actor Jack Soo had passed away of esophageal cancer on January 11, 1979. His last episode of the show was "The Vandal," which appeared in 1978. 

Harris(walking toward the coffee and stopping suddenly when he reaches the empty space where Nick's desk was) "Hmm, something's funny."

(Dietrich and Wojo are also there, Barney walks over.)

Barney: "Nick's desk." (looks sad and shocked)

Harris: (somberly) "Oh!" 

Barney: "They called about it last week. It completely slipped my mind."

The group stands silent, gazing at the spot.

Wojo: "I'm really gonna miss it."

(The others nod and say yeah)

Barney (looking sad) "Gonna miss a lot of things."

They fall silent again.

Dietrich: "I made coffee."

(The others seem to snap out of their sadness and follow him toward the coffee)

Dietrich: "It's not as bad as Nick's yet but..."

Barney pours a cup and takes a sip. 

Barney: "You're getting there!"

Everyone laughs and the episode continues.