|Wyatt Earp (1994) [Urilla Sutherland Earp]: Dies of typhoid, with Kevin Costner by her bedside. (Thanks to Nemanja and Kana)
The Last Supper (1995) [Paulie]: Poisoned (off-screen), along with all her friends, after Ron Perlman switches the poisoned wine they'd been planning to give him. We only see a stylized painting of Ron standing over the bodies. (Thanks to Christopher and JBA)
Double Jeopardy (1999) [Angela Green]: Killed in an explosion (off-screen) due to a gas leak (implied to have been arranged by Bruce Greenwood). We learn of her death a long time after the fact, when a neighbor informs Ashley Judd about it. Her obituary is later shown when Ashley looks it up at the library.
At Risk (2010) [Sykes]: Shot in the chest by Barclay Hope as she tries to stop him from shooting Daniel Sunjata. (Thanks to Dick Hertz)