I wouldn't try to DIY. I had a raccoon get into my attic through a deteriorating cupola vent, quite a shock when I stuck my head up in the attic and it popped its head up from behind a box. I called a pro and he came and looked through the attic. He didn't find it, and said they are nomadic; must have stopped in my attic temporarily, got spooked when it saw me, and moved on. He put some heavy duty wire screen under the attic vent, and the HOA eventually replaced the cupola. Fortunately, it didn't breed in my attic and only shredded a cardboard box.
Call the pro soon before it really wrecks your attic or you have little baby raccoons in addition to mama raccoon.