When a losing party seeks a new trial based on a claim of newly discovered evidence, the evidence must be in fact newly discovered, that is, discovered since the trial; it must be shown that it was not due to want of diligence that the movant did not discover the evidence sooner; the evidence relied on must not be merely cumulative or impeaching; and it must be such as would probably produce a different verdict if a new trial were granted. Imhoff v. Walker, 51 A.2d 309, 312 (D.C. 1947); Mahallati v. Williams, 479 A.2d 300, 305 (D.C. 1984); Frost v. Hays, 146 A.2d 907, 908- 909 (D.C. 1958); Potts v. Catterton, 82 A.2d 133, 134 (D.C. 1951). The granting or denying of a motion for new trial is within the discretion of the trial court and will not be disturbed on appeal unless an abuse of that discretion appears." Bradley v. Prince, 105 A.2d 253, 254 (D.C. 1954); accord, e.g., Wallace, 482 A.2d at 810 (citing cases).