* Bribes sought at all stages of investigation, group says
* Report follows U.N. call for more police resources
* Number of peacekeepers set to drop from 8,000 to 3,750
By Stella Dawson
WASHINGTON, Aug 22 (Thomson Reuters Foundation) - Rampant police corruption is impeding Liberia's development a decade after its 14-year civil war ended, and abuses should be reined in as the United ...