A pseudo-terrorist is a person who poses as a terrorist to gather information or to gain a tactical advantage. Pseudo-terrorist gangs worked in Rhodesia as the Selous Scouts. [1]

T. A. Lettieri wrote: 

The unit was the Selous Scouts, comprised of intelligence 
experts from the police and military, soldiers, and turned 
terrorist / guerrillas. Eventually  this small unit of 
scout trackers turned pseudo-terrorists expanded to a  
formidable counter-insurgency force of close to 1000 operators. 

They used stealth, guile and subterfuge during active ground 
reconnaissance to obtain current intelligence and ground truth 
on terrorist  infiltration and exfiltration routes, feeding and 
staging areas, arms caches,  base camps,and support networks. 
Within the Scouts members were fluent in the  native languages 
of Rhodesia (Shona being the most common native tongue) and 
understood the people, costumes and culture.
(http://members.tripod.com/selousscouts/pseudo_main.htm)
Pseudo-operations are common practice among police and military intelligence organizations worldwide. Even small police departments sometimes stage "sting" operations, to recover stolen property or to identify violators of pharmaceutical laws.

Pseudo-terrorist operations relying on turned "terrorists" sometimes fail. A Georgia prosecutor in 1993 allowed the release of Peter Langan, held on armed robbery charges, because the Secret Service said they needed Langan to find another man, court-marshalled Navy SEAL candidate Richard Guthrie, who was suspected of threatening the president. Langan eluded his handlers, continued to rob banks, recruited for the Aryan Republican Army, and frequented Elohim City in Southern Oklahoma where bomber Tim McViegh visited shortly before the Oklahoma City bombing.