SNOHOMISH, Wash.  (Metro)  -- The families of two teens brutally stabbed in a bathroom at Snohomish High School last year, are suing the Snohomish school district, Fairfax Hospital and parents of the 16-year-old female attacker. 

The lawsuit claims they could have prevented the attack that left April Lutz and Bekah Staudacher critically injured. 

Earlier this year, the unidentified attacker was sentenced to 13 years in prison after pleading guilty to attempted murder and assault.