sons of new york times bestselling author , ann rule , have been charged with theft and forgery in alleged financial exploitation case .
she has been in declining health since october 2013 and is ` vulnerable to undue influence ' , according to court documents .
michael rule , 51 , is accused of forging her signature on her checks amounting to $ 103,628 between march 2014 to february 2015 .
andrew rule , 54 , is accused of bullying her into giving him $ 23,327 and is said to have at times ` threatened suicide and screamed obscenities at her '
two sons , along with their two siblings , are given an estimated $ 25,000 combined monthly salary through mother 's corporation , rule enterprises .
ann rule has published 33 books including small sacrifices and the stranger beside me , and eight books have been made into movies .