Do you have step kids?

my worst is when his 9 year old son told my 6 year old son to get a knife a stab on of the other kids. i was horrified, i called my partner at work and boy was i pissed of and wanted him to come home a deal with it. i dont smack his kids and he dosent smack mine. i called him at about 10am and he got home at 4pm and he was working 20 minutes away. I told my partner if it happened again i was going to call the police, witch is what i should have done straight away. there have been other times as well but by far this was the worst. i have 4 children and do not want his son around any of them. i once found a pitcure he drew of himself cutting up my 14 year old daughter with a chain saw. i did go see welfair about him and was told not to let my children alone with him. he chased his own mother out of the house with a knife a wouldnt let her in untill his show was finished. his father says he will grow out of it, i watch him all the time we have him and have even said that i was going to take the other children out of the house untill he was gone home. i dont have a treasurable moment as far as this child goes, but there is a plus side my partners daughter, you could not wish for a better child and pleasent as she is. i love having her with us and have told her that she is more then welcome to come live with us any time she wants.