With what records? On most of these "refugees" there is little if any back ground documentation. But in the US we have documentation up the ass on everybody. Take for instance Tashfeen Malik, not the womans real name. (Tashfeen Malik (King) is a nom de guerre for a Muslim Jihadist from the annals of Muslim history. As he is known to Muslims “تاشفين ملك الموحدين” Tashfeen Malik Al-Muahideen, in English: Tafhseen King of the Unitarians (Muslims) and the conquerer of the west. The history stems from when Yusuf ibn Tashfin led the Muslim forces in the Battle of Zallaqa/Sagrajas. He came to Andalusia from Morocco to help the Muslims fight against Alfonso VI, eventually achieving victory and allowing the Muslims to remain in Spain for centuries. The battle has been symbolic for Muslim victory against the Christians.) A fine vetting job 
More to the point most of these fuckers have 3 or 4 different alias's.
do you understand what the word vet means? if i tell the dmv my name is john smith and it's really joe smith, i dont get a license. Are you really that daft? guess what? the ones without concrete records don't pass step one.
more so are you really commenting without knowing the vetting process? do you understand how ignorant that is?
1)firstly it gets started with the UN.
step one is refugee interviews, home country reference checks and biological screening
2) if they pass, only a small small percentage of them get approved for international relocation. basically anyone who's a special interest group. Torture, sexual violence, political persecution, multiple children, a female head of household.
3) and after they're recommended to america by the UN, the us govt does their own vetting(again confirming their identity or they get told to fuck off). most likely they'll be told to fuck off unless they've proven to be employable or already have family here.
4) then they get turned over to dhs, fbi, cia and the dod, where they're screened again. all along confirming their identity
So far 55% of all Syrian refugees are children under 10 and 25% of them are past the retirement age.