--Red wine.
--Saffron.
--Sodium carbonate.
--Sodium perborate.
--Curry.
--Tobacco and tobacco ash.
--Cardamom.
--Urate.
The Attack Site, Adjoining Roof, Via Carlo Cattaneo
--Trace: --Cumin.
--Enzymes: --Protease.
--Lipases.
--Amylases.
--Phosphates.
--Saffron.
--Sodium carbonate.
--Sodium perborate.
--Cardamom.
--Curry.
--Urates.
"As you can see," Ercole said excitedly, "there are similarities, common elements of the two. So it's likely that the same person at the smoking station, who left that trace, also was the attacker."
Not necessarily likely but certainly possible, Rhyme thought. Scanning the listings, considering possibilities, plugging in theories, unplugging others.
"Beatrice is working to tell us what the chemicals might mean."
"Fine, fine, fine, though I think we might not need her to."
The Forestry officer paused. Then he said, "But alone, they're just substances. How can we tell what they might be from? We need to see what they combine to become."
Rhyme muttered, "Which is what I've done. The chemicals at the smoking station--for instance, the acetic acid, acetone, ammonia, benzene, butane and cadmium--are, no shock here, from cigarettes."
"But they're poisons, aren't they?"
Thom laughed. "Don't smoke, Ercole."
"No, I don't. I won't."
Rhyme frowned at the interruption. "So, I was saying. At the smoking station, cigarette smoke residue. But, the other ingredients: I see laundry detergent. The spices, of course, are obvious. Curry. Indian food. Now, at the site of the assault? Laundry detergent and spices only. Now, think back, Ercole. On the roof, was there laundry hanging anywhere nearby? I've seen that everywhere in Naples."