The most recent posting, from March 15, is a slogan — Keep Calm and No Jodas (Don't be a Pain) — superimposed on an image of the Puerto Rican flag.
There are photos of him, seemingly on vacation, with youngsters who appear to be his children.
But most of the pictures show Lopez in work mode: driving his car in uniform, with his name tag displayed. There's one of him in front of a tank and several in which he is wielding heavy-duty firepower — including a shoulder-launched weapon.
"50 caliber sniper rifle. The dream of any shooter of long and precise reach," he wrote below one photo.
"Devastating effects on the target. This one belongs to Infantry Sniper Team HHC 1st AD 1 shoot 1 kill. Francisco you guys still have M-16 Lol."
There were few other details about Lopez's life on the page. He noted that he had left the Puerto Rico National Guard in 2010 and was now employed by the U.S. Army.
His Facebook handle and at least one picture he posted suggested he was a fan of Slipknot, the heavy metal band that has stirred controversy for its violent lyrics.