By J.D. Miles

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GARLAND (CBSDFW.COM) – Images of the sniper’s gun have emerged, and there are questions about how he got it and whether it was legal.

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The FBI and ATF are investigating the origin and the firepower of the rifle that caused so much carnage last week.

From the photo taken at the crime scene, which sources tell us is accurate,  the gun and ammo are undergoing ballistics testing to determine whether it was fully automatic and capable of firing an extremely high number of bullets per minute.

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Gun experts say it’s difficult to determine just looking at the photo.

“Listening to the audio from the different videos that are on the Internet,  I have to say it was a semi-automatic rifle (with) somebody pulling the trigger quickly,” says John Mannewitz, Targetmaster owner.

Its believed the sniper used steel jacket bullets which can pierce bullet-proof vests

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