It's not really about the word 'suggest'; the subtitle touts the chemical analysis, but the stronger evidence seems to be the structural analysis. They analyze

It's not really about the word 'suggest'; the subtitle touts the chemical analysis, but the stronger evidence seems to be the structural analysis. They analyzed several shards found in the same area. They found traces of sulfur, mercury, and oil on several of them. Most of them are concluded to be some sort of medical or perfume containers, because they're fancy. One of the shards is plain and thick. That's the one they think could have been a grenade, because it's plain and thick like ceramic grenades were.