Captor (noun)

A person or thing that captures or seizes something or someone.

Origin:

Early 15c., from old french capteur, from latin captor "seizer, taker".

Examples:

1. The captor demanded a ransom for the hostages.
2. The kidnapper is the captor of the child.
3. The soldier was the captor of the enemy general.
4. The camera is the captor of the image.
5. The captor held the key to the cell.