On Tuesday, the Associated Press and Fox 5 in Atlanta obtained photos from an FBI intelligence bulletin showing what's left of one of the bombs that exploded during the Boston marathon. As earlier reported, at least one of the bombs used in the attack was improvised from a conventional pressure-cooker.

Three photos show what Fox 5 describes as pieces of a stainless steel pressure cooker. The fourth photo shows a shredded black nylon bag, the same type investigators believe were used to disguise the bombs.

[Images via AP/Fox 5]