"The matter was placed in the Pinkerton's hands."

This article from the December 30, 1886  edition of the Brooklyn Daily Eagle tells the tale of a married Illinois preacher who absconded with his younger secretary. An excerpt:

“Chicago–Miss Fannie Matthews, who eloped with the Rev. C. B. Seals, of East Lynn, Ill., has been placed in her mother’s care by the Pinkerton Detective Agency. Seals was 50 years old, had a wife and family and was highly esteemed as a pastor. His victim was but 20. Seals was always made welcome in the Matthews household and spared no pains to praise Fannie. Her parents considered this in the light of a compliment, so highly did they regard the minister. At last the pastor gained the permission of Mr. and Mrs. Matthews to allow Fannie to act as his amanuensis. Fannie occupied this position for some time, but at last went away from East Lynn to visit some friends. The pastor disappeared a few days later, and suspicion was aroused for the first time. The matter was placed in the Pinkerton’s hands and descriptions of the couple scattered broadcast over the country. One of these was received by an officer in Alma, Ark., who recognized the description as that of the Rev. Charles Brady, who had preached there several times. Miss Matthews was living in Alma as his daughter. A detective and Fannie’s mother immediately went to Alma, but the couple had flown. Seals, alias Brady, found out that he was being shadowed and left, and the detective found that the couple had gone to St. Louis and from there to Canada.

Superintendent Robertson notified his operatives at London, Canada, and Seals and his victim were arrested day before yesterday when they stepped from the train. The pastor was allowed to go and the girl brought back to Chicago, where she was joined by her mother, who took her back to East Lynn.”