Menarik was born in 1889. On February 2, 1915 he walked into a New York police station and gave himself up, stating that he had killed eight elderly people with arsenic and chloroform over the preceding year, describing them as people who had outlived their usefulness. He gave his name as Frederick Mors, which is the name the case is filed under in most accounts.
He was examined, found insane, and confined to an asylum in 1915 rather than prosecuted. In 1916 he escaped.
That is the whole of the accessible record. There was no trial, no conviction and no judicial finding of any kind about the eight deaths. Whether the confession was true was never determined, and the entry is marked as one in which nobody was convicted.
Nothing records what became of him after the escape.
A voluntary confession by a man later found insane, never tested and followed by his disappearance from the record, is not a basis for a victim count, and the figure of eight or more in this roster should be read as an allegation he made about himself.