FLINT -- Flint firefighters have had their hands full once again this weekend, with reports of 12 fires by midnight Saturday.  The first came in around 1:38 am at an abandoned house.  Department officials told NBC25 they have received 107 calls so far this month alone, effectively tripling the 37 calls received this time last April. Meanwhile arson investigators are backed up with an increased workload and ask anyone with information on various fires to give them a call.