A Louisiana felon was arrested for supplying the gun used by deranged Army vet dad Shamar Elkins to massacre his seven kids and nephew, as federal authorities released the first photo of the bloody weapon.

A Shreveport man in his 50s has been arrested for allegedly helping the suspect in the Cedar Grove mass shooting obtain a gun.

Charles Ford, 56, of Shreveport, was charged on Tuesday with illegally possessing a firearm as a felon and lying to federal agents.

The killer ended up shooting the eight children — including seven of his own — execution-style Sunday morning.

Shamar Elkins, suspected of killing 8 children in Shreveport, was fatally shot by police; reports suggest possible mental health struggles.

The Louisiana gunman who murdered eight children — including seven of his own — before he was killed was a 31-year-old Army vet who posted a picture of himself with one of his daughters hours before Sunday’s massacre.

There is a name for the crime police say Shamar Elkins committed when he fatally shot eight children in Shreveport on April 19: filicide, or the killing of a child by their parent. Parents, not strangers,