Lewiston officials are going to crack down on abandoned buildings following three fires that destroyed nine apartment buildings and left more than 180 people homeless. One hundred firefighters battled the latest blaze early Monday that destroyed two buildings that were vacant. A third building was damaged. No one was hurt. City officials say police, fire, and public works departments will work with code enforcement officers to inspect vacant houses in the area where the fires occurred. Mayor Robert MacDonald put owners who have neglected their properties on notice, saying, ‘‘The hammer’s coming down.’’ Also Monday, two 12-year-old boys charged with causing the first two fires remained in custody after appearing before a judge during a closed-door hearing. The cause of the third fire remains under investigation.