Some of the wicked members of the northern kingdom were killed before the main body of Samaria was taken captive to Assyria. This likely occurred while the Israelites were under siege to the Assyrians for three years (1 Kings 17:5). No record specifically describes how many died in the wars and siege of the Assyrians.
The record is more complete regarding the destructions which occurred in Jerusalem when the Babylonians took the city:
’Therefore he (the Lord) brought upon them (the Jews) the king of the Chaldees, who slew their young men with the sword in the house of their sanctuary, and had no compassion upon young man or maiden, old man, or him that stooped for age: he gave them all into his hand…
And them that had escaped from the sword carried he away to Babylon’ (2 Chron 36:17,20).