All known populations were completely killed off in late 1991 or early 1992.

His character was later killed off in the fourth season finale.

At least then we'd know it would be killed off for sure in the next year or two.

Derek appeared to be killed off in the final episode of the series.

Andy ended up being the first main character to be killed off in 1986, just over a year after the show began.

He is later killed off in June 2007, following the actor's decision to leave the cast after only nine months.

The character was killed off in the summer of 2005.

The Flake girl was finally killed off after 40 years, in 2004.

Her character was killed off in the last episode of the series.

The character is expected to be killed off in late 2013.