Survival of the fittest

It was 3 a.m. it was my watch, our compond has been holding up pretty good. It was time for the hourly patrol and as i came up on the supply shed and noticed the door was open. As i approched, a zed came rushing towards me, I put one round in its head and it was stopped in it's tracks, But it turns out it was the brother of one of our survivers we picked up in the last town and apon inspection there was no forced entry into the compound. Rumours are this guy now has it out for me....... what should i do?