The general size, handle shape and red coloring remind me of a hay hook. Could be someone repurposed a hay hook for some unknown purpose. As for using it to sew up sacks, all I've ever seen used for that purpose is a sack needle, looks like a very large sewing needle with a spear shaped point. When I was young I worked with an old guy with lots of great stories. One day he told me how his mother cured his father's drinking problem. Seems his dad was a payday drunk and used to come home full and slap his mother around. One night after he passed out, she took a sack needle and some twine and sewed him into the bed sheets, then proceeded to beat him bloody with an irrigating shovel. He never touched another drop as long as he lived.