Diagnosis Murder

"Mr. Kendall, in the past few months there have been a number of doctors who have mysteriously disappeared, or whose deaths were either alleged to be ccidents, or were suicides, or they were actually murdered."   
Kendall made a mental note to find out about these 'other  doctors.' "A number of doctors you said. How many are  
we talking about?" 
 Mrs. Eaton thought for a few moments. "To my knowledge  there have been at least eight cases in the past six months. There may be a whole lot more that I know nothing about."