Donald Mayer, 51, was found dead inside his family’s home on Cider Hills Drive in the Village of Waukesha on February 28, 2025, though investigators later determined he had actually been shot and killed on February 11. His wife, Tatiana Casap, was also found dead in the residence after a welfare check prompted by concern from Mayer’s mother and by school officials reporting Tatiana’s son Nikita Casap had been absent for an unusual length of time.

Prosecutors charged Nikita Casap with two counts of first-degree intentional homicide, accusing him of deliberately shooting Mayer and Tatiana, and added felony counts including hiding the bodies, theft and identity-related offenses. Investigators said a school acquaintance reported Nikita had discussed killing his parents before the deaths, and prosecutors alleged he remained in the house for roughly two weeks after the shootings, used his parents’ resources, and eventually fled Wisconsin with cash, passports and other property. What details about motive, the timeline in those two weeks, or other possible witnesses remain unclear to the public; anyone with information about Donald Mayer, the household on Cider Hills Drive, or those final weeks is asked to come forward.