As there is no evidence, it could be sensitive if we have any doubt (e.g. CCTV). One good way is to make sure that more than 1 person check the money in cashier tray, and then more than 1 person put the same amount together in the envelope sealed with signature.
When the money in cashier tray was checked, who counted the amount? Did the same person hand over the cash to APCD? Anyhow, it must be better for those who take care of cash by using their initial signature.