Frank testified he was busy with accounting work, supported by exhibits of his financial sheets, indicating he was occupied during the estimated time of the murder, as per his August 18, 1913, testimony (Testimony of Leo Frank). Colleagues, like Herbert G. Schiff, corroborated his workload

Weak alibi. Remember, this was back when a spreadsheet was a literal sheet of paper you wrote calculations on, so it's not like they could check his claim by looking at the metadata.