/usr/lib/libtcmalloc_debug.so.4 is in libgoogle-perftools4 2.5-2.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libtcmalloc_debug.so.4.3.0
/usr/lib/libtcmalloc_debug.so.4.3.0