Original sentence: The Khmer Rouge forces regrouped along the border with Thailand and retained the structure of the DK state in regions they controlled.The PRK government was a puppet government of Vietnam, similar to that installed in Laos in December 1975
Edited sentence: However, the Khmer Rouge forces regrouped along the border with Thailand and retained the structure of the DK state in regions they controlled.The PRK government is believed to have been a puppet government of Vietnam, since it was installed with Vietnamese help