/usr/lib/libboost_prg_exec_monitor-mt.so is in libboost-test1.48-dev 1.48.0-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libboost_prg_exec_monitor.so.1.48.0
/usr/lib/libboost_prg_exec_monitor.so.1.48.0