to prime a witness

He is a product of the merchant marine and is one of the officers called Mustangs who entered the navy during the Civil War.

[…]6) Bureaus for appeasing tenants engaged in reclamation and cultivation of the wastelands were established in Beinan, Qilai and Puli. (Private Law of Taiwan, Property Rights, Vol 1 pp 9-12)

But when he found that some of his interrogatories were evaded, and others answered undecisively, the look of gentleness which he had assumed, vanished, and his brow wore the cloud of disappointment and of anger.