How does one work with problematic clients in a treatment group?

Recently in the news, a client with PTSD was thrown out of a group at a VA hospital for his behavior. He later came back and shot the three female therapists who had been working with the group, one of which was 7 months pregnant. How can social workers prevent such situations? 1. APA Format 2. Title Page includes Title, Name, University, Instructor, Course, & Date 3. Include In-Text Citations 4. References Page 5. 3 Pages 6.