ITWAS JUST one of more than 2,000 murders in 2009 in Ciudad Juárez, a Mexicancity across the Rio Grande from El Paso, Texas: someone shot in an alley, no witnesses. no witnesses作状语吧？
谢谢各位老师！
是省略。
张道真《英语语法大全》下册，第 388-389 页：
4．there 或 therebe 有时可以省略。
（There）Mustbe something wrong．
（There）Maybe someone making trouble．
（There）Won'tbe anybody getting interested．
（There）Shouldbe no time left for arguing．
Iwill pay you in three days，and（thereis）no mistake．
（There is）Nofool like an old fool．
（There is）Nooffence taken when none is meant．
（There is）Aneye for an eye，and atooth for a tooth．
（There is）Notellingwhat he is doing．
（Is there）Anynews？（There is）Nothingparticular．
—在简短的通告、标题、电报等中（省略 be）
Shoes（are）onsale．
Everysort of metal construction（is）undertaken．
English（is）spokenhere．
Nodogs（are）allowed．
Admission（is）free．
Rosyprospects（are）nowyours．
Result（is）encouraging．
ParisTalks（Are）HopefulBut Delicate．
Father（is）ill．
Johnsonfamily（is）coming．
Help（is）wanted，skill（is）notnecessary，female（is）moredesirable，salary（is）high．
所以，网友的句子可以还原为：
someone shot in an alley, there no witnesses. 独立主格结构作状语。
或者
someone shot in an alley, no witnesses.
或者
someone shot in an alley, no witnesses.
