Simplify the following text for a Grade 13 native English-speaking person.
Original: In the same spirit , Miroslav Filipovic-Majstorovic , once captured by Yugoslav forces , admitted that during his three months of administration , 20,000 to 30,000 people died . Since it became clear that his confession was an attempt to somewhat minimize the rate of crimes committed in Jasenovac , having , for an example , claimed to have personally killed 100 people , extremely understated , Miroslav 's figures are evaluated so that in some sources they appear as 30,000-40 ,000 .
Simplified: In the same spirit , Miroslav Filipovic-Majstorovic , once captured by Yugoslav forces , admitted , in attempt to somewhat minimize the rate of crimes committed in Jasenovac ( e.g. Miroslav claimed to have personally killed 100 people , extremely understated ) , that during his three months of administration , 20,000 to 30,000 people died , whereas in other sources it is displayed as 40,000 .