In 1897, Rosenblum began an affair with Margaret Thomas (née Callaghan), the youthful wife of Reverend Hugh Thomas, shortly before her husband's death. Rosenblum met Rev. Thomas in London through his Ozone Preparations Company because Thomas had a kidney inflammation and was intrigued by the miracle cures peddled by Rosenblum. Rev. Thomas introduced Rosenblum to his wife at his manor house, and they began having an affair. On 4 March 1898, Hugh Thomas altered his will and appointed Margaret as an executrix; he was found dead in his room on 12 March 1898, just a week after the new will was made. A mysterious Dr. T. W. Andrew, whose physical description matched that of Rosenblum, appeared to certify Thomas's death as generic influenza and proclaimed that there was no need for an inquest. Records indicate that there was no one by the name of Dr. T. W. Andrew in Great Britain circa 1897.