The Devil Loves Me - Margaret Millar

Psychologist-detective Paul Prye is getting married—or at least he would be if one of the bridesmaids didn't collapse in the middle of the ceremony. It's a case of poison—Prye knows because when he goes to look for the ring he finds instead a note left by the would-be murderer.

But who would want to kill silly, sweet Jane, the bride's simple-minded if somewhat nymphomaniac cousin? Is it possible Jane was not the intended target? The ultra-dry Toronto police detective investigating, Inspector Sands, has reason to suspect Paul Prye himself, not least because the bridegroom was able to correctly guess the poison used and tell the hospital in time to employ an antidote and save the girl's life.

Any such suspicions are dispelled when another member of the wedding party goes missing. The bride's family is thick with secret romances and grudges, which come to light one by one. Disaster is at hand—and not just because the erstwhile bride and groom have received fifteen coffee tables as gifts. Perhaps together the two detectives—the policeman and the psychiatrist—can solve the riddle before the bodies begin to pile up.