When he is sentenced in March, a Rhinelander man who poisoned a dog could get up to three-and-a-half years in prison.  Robert Runnerstrom admitted using toilet bowl cleaner to kill the dog last May.  Police say a woman accused him of poisoning her boyfriend’s dog.  A woman at his home told investigators Runnerstrom said the dog got into some poison in his bathroom.  A piece of wood was found in that bathroom, with some blood nearby.  The dog was found outside in a bag, suffering from a skull fracture.