learn how to search for idioms yourself:
search Yahoo with:
"stop someone in their tracks" dictionary
(quotation marks are important)
one of the result pages is:
-------------
http://idioms.thefreedictionary.com/puts+a+stop
stop (someone) in their tracks
if
something stops someone in their tracks, or if they stop in their
tracks, they suddenly stop what they are doing because they are so
surprised.
A loud scream stopped me dead in my tracks.
He opened the door and stopped in his tracks.
A complete stranger was sitting in his office.
---------------