An alibi told by the accused is a story. An alibi told by a stranger's paperwork is a fact, and Exhibit E is paperwork. It is the night-watch heron's logbook — the running record a working heron keeps of everything that moves on the water after dark, kept not for PeePoo, not against him, but simply because that is the job. Surrendered voluntarily and opened to page 47, it does something Exhibit C, the timeline, cannot do alone: it corroborates the honest frog's whereabouts in a hand that had no reason to lie for him and every professional reason to be accurate.
The same moon that timed the alibi timed this log. Two exhibits, two methods, one honest frog, exactly where he said.
The relevant entry is plain to the point of boredom, which is what makes it deadly. A little before the hour in question the heron logged one frog, alone, moving unhurried through the far reeds — two ponds off from the grate — and then simply sitting there. Not signing. Not passing anything. Not meeting anyone under a grate. Sitting in the reeds being decent, the single least suspicious thing a frog can be caught doing at that hour. The log does not editorialize. It records a lone amphibian at rest, two ponds from where a crime was, at the minute the crime was.
The time-stamps are the exhibit's spine, and they were checked against the one clock in the swamp no frog can wind: the moon. A night-watch heron does not carry a pocket-watch; it tells time by the angle of the moonlight on the water, and that angle is not a matter of opinion. The court cross-checked page 47's entries against the moon's position for that night and they matched to the notch. The same moon that timed the alibi in Exhibit C timed this log. Two exhibits, two independent methods, one honest frog, exactly where he said, at exactly the hour they say the ledger was touched.
What Exhibit E proves is redundancy, and in an honest case redundancy is a virtue. Exhibit C put PeePoo three ponds off on the strength of an alibi and a gnat. Exhibit E puts him two ponds off on the strength of a working heron's ledger and the moon — a wholly separate record that happens to agree. When the alibi and the night-watch and the sky all place the same frog in the same reeds, the only frog left unaccounted for at the grate is the one with the hook. The log does not name him. It does not have to. It just proves he was not the frog it saw.