EMBED >More News Videos Nia Wilson was just 18 years old when she was killed in an unprovoked stabbing at MacArthur BART station in Oakland. Fighting through sorrow, her friends, family, and the community at large are mourning the teenager who brightened the lives of those she knew, and has inspired many who never got the chance.

CONTINUING COVERAGE ON DEADLY BART STABBING:

DUBLIN, Calif. (KGO) -- The family of Oakland's MacArthur BART station stabbing victim Nia Wilson is suing the transit agency, saying it should have done more to protect her and her sister.Investigators believe a transient randomly attacked Wilson at the station.The family's lawsuit alleges BART never should have allowed suspect John Cowell into its stations. Cowell had been stopped for fare evasion in the days before Wilson's murder and was arrested at a BART station the day after.