Security was lacking at the Brooklyn YWCA when one resident stabbed another 80 times with a kitchen knife, according to a lawsuit filed by the victim’s family.

Liza Millet, 48, was killed in the bloody May 2016 assault by fellow YWCA resident Dorothy Curry, who used the 6-inch blade in the first homicide of the YWCA’s 128-year history, police said.

The facility shouldn’t have let Curry onto the Third Avenue property with the knife and failed to monitor security cameras or respond quickly, Millet’s family said in a Brooklyn Supreme Court lawsuit.