21.   Meanwhile, a picture of a troubled, financially insecure man emerged from acquaintances after the mass shooting early Tuesday.

22.   Police called it the worst mass shooting in Philadelphia in three decades.

23.   Reports of such mass shootings appear to have circulated routinely among U.S. Army staff officers.

24.   Such mass shootings have occurred on multiple occasions in the Russian army in recent years, but have been relatively rare in other former Soviet republics.

25.   The mass shootings, taking place for the past several mornings, have drawn harsh criticism from the media and others.

26.   The recent mass shooting at an Oregon school was the latest in a never-ending string of horrors.

27.   There have been numerous mass shootings in the past few years.

28.   Witnesses describe brutal mass shootings.