Chinese prosecutors began investigations into 54,249 officials, including both high-ranking "tigers" and lowly "flies," for suspected involvement in 40,834 graft cases in 2015, a report said Sunday. 

All in all, prosecutors looked into 4,490 graft, bribery and embezzlement cases involving more than 1 million yuan each, said a report on the work of the Supreme People's Procuratorate (SPP) to be delivered by Procurator-General Cao Jianming on Sunday.