Nurse guilty of killing patients

http://news.bbc.co.uk/2/hi/uk_news/england/west_yorkshire/7267409.stm

Colin Norris, 31, had denied killing the four women at Leeds General Infirmary and St James's Hospital in 2002 by injecting them with insulin. After a trial at Newcastle Crown Court a jury took four days to find Norris, of Egilsay Terrace, Glasgow, guilty of four counts of murder. He was also convicted of the attempted murder of another patient. Norris will be sentenced on Friday. The trial heard that suspicions were raised when Norris predicted the death of Ethel Hall, a patient who later slipped into a fatal coma.

I think that this is very scary that a nurse would kill patients in there own hospital. Are we safe anywhere?, that is my question. Could we add more security for the sake of the patients