Simplify the following text for a Grade 7 native English-speaking person.
Original: In March 2009 , the final results of the DNA testing were published by Dr. Michael Coble of the US Armed Forces DNA Identification Laboratory , proving conclusively that the remains of all four Grand Duchesses have now been accounted for , and no one escaped .
Simplified: In March 2009 , the last results of the DNA testing were published by Dr. Michael Coble of the US Armed Forces DNA Identification Laboratory . This proved that all four Grand Duchesses were murdered .