How does Lee increase the level of suspense as the children being walking home?

Strange noises:

“Hush a minute, Scout,” he said, pinching me.

We walked along silently. “Minute’s up,” I said. “Whatcha thinkin‘ about?” I turned to look at him, but his outline was barely visible.

“Thought I heard something,” he said. “Stop a minute.”

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"I said it more to convince myself than Jem, for sure enough, as we began walking, I heard what he was talking about. It was not my costume."

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The children determine they're being followed:

"Our company shuffled and dragged his feet, as if wearing heavy shoes. Whoever it was wore thick cotton pants; what I thought were trees rustling was the soft swish of cotton on cotton, wheek, wheek, with every step."

Source(s): To Kill a Mockingbird