(06-06) 20:44 PDT HALF MOON BAY -- An 18-year-old woman with a knife was shot and killed Tuesday night by a San Mateo County sheriff's deputy near Half Moon Bay, authorities said.

The woman, Yanira Serrano-Garcia, had special needs and had stopped taking her medication, relatives said Wednesday. The family called for an ambulance Tuesday night hoping she would receive medical help, said her aunt, Irma Miramontes.