The head of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives says he fears that a drumbeat of mass shootings and other gun violence across the United States could make Americans numb to the bloodshed, fostering apathy to finding solutions rather than galvanizing communities to act.

Director Steve Dettelbach’s comments to The Associated Press came after he met this past week with family members of some of the 18 people killed in October at a bowling alley and a bar in Lewiston, Maine by a U.S. Army reservist who later took his own life.

He said people must not accept that gun violence is a prevalent part of American life.