A Las Vegas woman with a 'firearm fascination' allegedly killed her model boyfriend after she set off a gun she was posing with during an ill-fated photoshoot.

Allysandra Blea, 20, stands accused of murdering Mark Santiago Gaughan, 23, as he snapped her pictures on Saturday morning around 5am near Sin City's Northwest Valley.

Police told KLAS Blea, who has a bullseye tattoo on her chest, and another woman were apparently the subjects of a weapon-filled Polaroid photoshoot.

When the two women were posing with a gun, Blea allegedly discharged the weapon. The bullet hit Gaughan and he died shortly after.

Authorities were called to the scene to respond to an 'accidental shooting.' They later retrieved photos of the women posing with knives and guns, KLAS reported.