Robert George Clements was born in 1880 in Belfast, Ireland. He graduated in 1904 and became a physician, earning a fellowship with the Royal College of Surgeons. Throughout his career, Clements was well-regarded in medical circles.

Clements married four times, with each of his wives predeceasing him under suspicious circumstances:​

Edith Annie Mercier (First Wife): Married in 1905, Edith was active in the Ulster Women's Unionist Council and the daughter of a wealthy Belfast grain merchant. She died in 1920 at age 40, with the cause listed as "sleeping sickness."

Mary McCreary (Second Wife): The daughter of an Irish industrialist, Mary married Clements in 1922 and died in 1925 at age 25, reportedly from endocarditis.

Sarah Kathleen Burke (Third Wife): Known as Kathleen, she married Clements in 1930 and died on May 27, 1939, also from alleged endocarditis. Her body was cremated quickly, despite police attempts to halt the process due to rising suspicions.

Amy Victoria "Vee" Barnett (Fourth Wife): Married in June 1940, Amy was the daughter of one of Clements's patients. She died on May 27, 1947, under suspicious circumstances. Initially diagnosed with myeloid leukemia, a subsequent autopsy revealed morphine poisoning.

Upon discovery of the true cause of Amy's death, authorities moved to arrest Clements. However, he committed suicide via morphine overdose on May 30, 1947, before he could be apprehended.