First of all I 'm sorry my English is not very good.
I am feeling very low at this point. I am a single mother working full time. I have a 9 year son. I take him to my office when I work. My boss is a kind lady and allows me to keep him at office (he has a room of his own in office). He is a well behaved boy and liked by everyone. He is intelligent and does well in his school. We are close. I have always been proud of him and have prided myself on being a good mother. Until today.
My friend sent her daughter (she's 9 too and happens to be a friend of my son) to my place (home) as she was going out for the day. This has happened many times before. I don't mind taking care of the little girl as she is a well behaved kid too. So I cooked lunch for the 3 of us and later we played cards. I was feeling drowsy so I let them continue playing. I went to my room and took a short nap. Within minutes the my friend's daughter came running to my room screaming. I tried to calm her while calling out for my son. He came to my room and stood quietly. The girl told me that while they were playing they had some minor misunderstanding and as a result my 9 year old son lost his temper. He went to the kitchen and came back with a knife and put it to her throat! I was so shocked at hearing this and demanded my son for an explanation but he remains quiet. He is in his room now. I am at loss, don't know how to handle this situation.
What should I do? Have I failed as a mother?