A new trial based on after-discovered evidence may be granted under the limited circumstances where the defendant shows that the evidence: (1) was discovered after trial; (2) could not have been secured for trial with the exercise of due diligence; (3) is not merely cumulative, corroborative or collateral; (4) is material, and such is likely to produce a different result at another trial. See Odum v. Commonwealth, 225 Va. 123, 130, 301 S.E.2d 145, 149 (1983). The granting of a new trial based on after-discovered evidence is within the sound discretion of the trial court. See Yeager v. Commonwealth, 16 Va. App. 761, 767, 433 S.E.2d 248, 251 (1993). The motion must be supported with "facts showing the lack of knowledge of such evidence, the efforts made to obtain it, and why those efforts failed." Mundy v. Commonwealth, 11 Va. App. 461, 483, 390 S.E.2d 525, 537 (1990) (en banc), cert. denied, 502 U.S. 840, 116 L. Ed. 2d 95, 112 S. Ct. 127 (1991).