In the process of doing something considered criminal or otherwise wrong; used to emphasize the eye-witness evidence.(phrase)
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Use "in the act" in a sentence
"When the enemy endeavored to erect a battery themselves, Captain William Washington, cousin to the general and a superb cavalry officer, together with Lieutenant James Monroe, raced forward with the advance guard and, “taking two pieces in the act of firing, drove the artillerists from their guns.”"
"Alexander, caught in the act and unwilling to challenge his father so soon after his return from exile, admitted he had behaved imprudently."
"According to the legend — of which, however, St. Avitus, a witness of the baptism of Clovis, was ignorant in the fifth century, and the first trace of which appears in Hincmar — the holy ampulla was brought by a dove to St. Remigius when he was in the act of crowning Clovis."