I don't think it's right to do that. If people find out that it's not your design and it happened to be theirs, lawsuits may be filed against you. I know I'm exaggerating, but it's the truth. If there is a way for people to get money from what you're doing, then people will do it. I suggest that you tweak the sketch a little bit so it's not the exactly the same as the sketch you found on Google.