Need someones expert advice

I know someone who had twins on August 19th, fraternal. She lied all through her pregnancy about due dates and stuff. She was with a few different men when she got pregnant but because of her due dates she came up with it was narrowed down to 2 men. She was with one man on the weekend of December 8th and 9th, and then with another name on December15th. We also know that her LMP was between Nov 20-27th. She said when they took her twins that she was 38 wks pregnant. One min. she said she was due September 1 or 2 then was told by people who went to the same doctor as her that she was really due on August 27th. I know you can't give a definite answer, the only way we will know who the father is is if she gets a DNA test, but she saying she doesn't need one because they are the mans that she was with on Dec. 8th or 9th. I just want to see what everyone else thinks when did she conceive on Dec 8yh, 9th or 15th? What do you think? There has been so many lies told i don't know what to believe. But if she would've conceived on December 15th she would of only been about 35 wks. and also the babies both weighed 6 pds a piece. Just give me your imput.