In 1900, Thierry was accused by the Governor of German Togoland of poor management of the station's expenses and reckless diplomacy with the neighbouring French colonialists.
In addition the governor wrote:"Thierry's main activity consisted in leading the life of some kind of mercenary, repeatedly absconding from the station for many months and undertaking one punitive expedition after another, resulting in abundant spoils of war which provided the basis for his business.
In 1903 he accompanied Governor Jesko von Puttkamer on his trip to Lake Chad and on this occasion was appointed first Resident of the colonial province of Adamawa on 20 September 1903.
A year after his death, in 1905, the case of Thierry's brutality against Africans was brought back to the spotlight as parliamentary debates on colonial affairs took place after several scandals involving officers and missionaries in German-Togo hit the headlines in the German press.
The official parliamentary indulgence stipulated that Captain Thierry had shot down the father of the pupil of the Catholic mission in Lomé, after he had climbed up a tree to flee from the officer.
Amongst those 1700 objects were weapons and personal items he had looted from his leading military expeditions in German Togoland, including the belongings of Biema Asabiè and other Anufo leaders of Sansanné-Mango.