The memo nobody read

There was a memo warning that the fence was torn. It was sent to six people, read by none of them and filed by all of them. Some clues in this case come as riddles. If one stumps you, a hint will solve it. Not every row and column has to be occupied.

Suspects

• Ascenso, the chief of staff: He got the memo and forwarded it to himself so he wouldn't forget. He forgot.
• Belisa, the secretary: She stamped the memo "urgent". The stamp did more work than anyone that day.
• Cirilo, the general: He signed the memo without reading it, as always. He says it keeps him from being influenced.
• Diamantina, the minister's adviser: She summed up the memo in three lines. Nobody read the three lines.