briefed =(was) briefed (about the rioting mission)?

Context:
There is also increasing evidence suggesting that organised groups were involved in instigating attacks of arson and vandalism aimed largely at ethnic Chinese neighbourhoods. Rioters reportedly arrived at various targets in Jakarta simultaneously with gasoline bombs and other weapons and initiated the violence. Albert Hasibuan, a member of the National Commission on Human Rights, said human rights workers had talked with a rioter who said he had been recruited, briefed, paid and transported by unidentified men, who provided him and others with stones and gasoline bombs.

More:
http://www.hrsolidarity.net/mainfile.php/1998vol08no09/1630/