Raccoons are known to be extremely social animals, so you should never underestimate a problem by assuming you only have one or two animals to deal with. Raccoons like to travel with large family-like groups and finding several of them in the same living space is very normal.
Mother raccoons very often will look for safe places to keep her kittens right in your own home. Whether it be in the chimney, attic, or other hollow spaces, it doesn't take long for them to den up.
Although it may seem like an easy to fix job, you should never try to handle a raccoon problem on your own. Attempting to smoke out, seal out, or trap raccoons on your own could potentially trap or kill the raccoons in a hard to reach space and will become a larger problem as they die and begin to decompose.