Too many of our countrymen had died. Scientists were looking for answers as well and were under pressure from the military and higher powers. Nuclear power wasn't available but experimentation with genetics was highly advanced and seemed to be their only hope. They were to create a substitute for manpower using the results of genetic manipulation.
Scientists hoped to create a ultra loyal and trainable, very large, fighting type animal such as a regular canine would be. To be a successful combination of genes, it was to have had the fighting ability and stealth of the feline species with the loyalty and train-ability of the canine species. For a larger size they threw in genetic dna from fossilized bones of the extinct Smilodon. Results looked promising and many litters were created and brought to age. Promise was as far as the scientists got.
What resulted from their experimentation was a abomination. Instead of being a single animal it was a combination of all 3. Their results yielded a 800 pound 3 headed, 3 tailed feline with a canine head in the middle. This creature they thought to train as expendable fighting machines for their war (but loyal like a canine.) As it progressed, the scientists were finding that the more feline traits were coming forward and there was not enough loyalty and lowered ability to learn what would be needed to use on the battlefields. Although a normal feline house cat can be trained, and canines are loyal and very trainable, the resulting Feninodon could only be taught very few commands. Although the animals grew extraordinarily fast and would have been an excellent weapon had the experiment been a success, the scientific community found it to be a failure and dictated that all experimentation to date must be destroyed.
One of the scientists was enlisted to dispose of all the creatures that had been created but the scientist just could not bring himself to exterminate the cubs after the adults had been disposed of. This mistake was costly. He was only able to bring them to infancy (Even then about 3 foot tall) before they escaped his enclosure and now roam the planet and can mate with large felines like lions and tigers as well as wolves and other canines. They are now free roaming and rapidly populating the planet. The resulting offspring can take on many forms, 2 heads, 3 heads, 1 head and or any combination of the genetics or even throw back and be a single (much larger than normal) animal. Other than mankind it has no known predators and so mankind is looking for what to do now. What shall we do?
I hope you like my little story about the Fenineodon. (Feline, Canine, Smilondon) I left it open ended as to what happens after they start to pupulate lol I mean populate the planet. I used your likes to create the colors, part African Wild dog and part Snow Leopard with Cheetah thrown in for spice.
I can easily do weapons if you want, but I think if this animal were to exist, it is weapon in itself which is what it was designed for to begin with. 
