Taken from Booms Website, Looks like this is going to be a series instead of a mini due to all the support it received.
BOOM! Studios announced today that SOMETHING IS KILLING THE CHILDREN , the brand new horror series from GLAAD Award-winning author James Tynion IV ( The Woods, Justice League ) and artist Werther Dell’Edera ( Briggs Land ), has been promoted to an ongoing series due to the overwhelming early support from retailers and fans in advance of its debut on September 4, 2019 at comics shops.