It is a Sunday morning and a man comes to find his wife dead. The maid said she was cleaning the kitchen, the mailman said he was delivering mail, the nanny said he was teaching the kids, and the farmer said he was harvesting his crops. Who done it?

Nanny, men are mannies but not nannies.

Well, there isn't much evidence of what happened such as where the wife was killed, who else was in the house at that time, or any DNA samples found, but I could make an estimate about it being the maid. Mailman was outside delivering mail, farmer was outside harvesting, and the nanny must have been busy with the kids so she shouldn't have done it especially in front of kids. The Maid was inside and alone (Probably with the wife) and had access to sharp objects such as knives.

In short, I believe the maid did it.