I did the same thing for a friend of a friend. He needed a job bad. I went to bat for him and he got hired. Worked like a mule! He kept three shirts in his locker he worked/swet so much... He worked great for about 2-3 months then went AWOL...
They kept asking me where he was and the third day of no-call-no-show, they fired him. My friend handn't heard from him either.... then we did, his wife got an insurance settlement and decided work wasn't for him!
Made me look bad just like you. From now on, I don't refer no-one unless I know them personally.