Emotionlessly and heartlessly; with deliberate cruelty or callousness.

synonym: cold-bloodedly.

Roget 826: like patience on a monument smiling at grief" [Twelfth Night]; aequo animo [Lat.], in cold blood etc. 823; more in sorrow than in anger.   

Roget 823: insensibly etc. adj.; aequo animo [Lat.]; without being moved, without being touched, without being impressed; in cold blood; with dry eyes, with withers unwrung^†.   

Roget 620: intentionally etc. adj.; advisedly, wittingly, knowingly, designedly, purposely, on purpose, by design, studiously, pointedly; with intent etc. n.; deliberately etc. (with premeditation) 611; with one's eyes open, in cold blood.    for; with a view, with an eye to; in order to, in order that; to the end that, with the intent that; for the purpose of, with the view of, in contemplation of, on account of.    in pursuance of, pursuant to; quo animo [Lat.]; to all intents and purposes.    ... show more

Roget 611: advisedly etc. adj.; with premeditation, deliberately, all things considered, with eyes open, in cold blood; intentionally etc. 620.