A Midsummer's Equation (Detective Galileo #3)

by Keigo Higashino

Though the union card had told Nishiguchi that Tsukahara was a former cop, the revelation he was in Tokyo homicide came as a surprise. Yet it did make one thing clear: now he knew why the widow had sounded so collected on the phone moments after learning of her husband’s death. She’d probably spent many long years anticipating that very call.

“The blue sparks are copper, green is barium. Red sparks are strontium, and yellow are sodium. All metals. As you can see, each metal and metallic compound gives off a distinct color when it burns. This is called a flame reaction,”