Peter J. Keenan was born in Hell’s Kitchen during the Roaring Twenties.  Shortly after his 20th birthday in 1942, he enlisted in the United States Navy.  During World War II he served as a radio operator on a submarine in the South Pacific and South China seas.  In 1946, following his discharge from the Navy, he joined the New York Police Department.  He spent twenty years as a uniformed police officer in the patrol branch.

In 1967, after retiring from the police department he became a Revenue Officer and later a Special Agent, Criminal Investigator with the United States Treasury Department. From 1981 until his retirement from Federal civil service in 1989 he was assigned as the Internal Revenue Service’s Intelligence Representative to the United States National Central Bureau of INTERPOL located in Washington, D.C. Over 135 countries were affiliated with this famous criminal investigative agency during that period. His assignment entailed occasional foreign travel to the international headquarters of INTERPOL at St. Cloud, located outside of Paris, France, and various countries in South America and the Caribbean. Constables on Patrol is Peter Keenan’s first book.

According to the book description of Constables on Patrol, it “is a police story centering on a recently discharged U.S. Navy veteran of World War II who commences a career as a New York City police officer in 1946. An experienced, dedicated police captain, recognizing in this new officer those qualities which he believes justifies the term New York's Finest attributed to the police force "adopts" the new recruit. The officer, exhibiting wisdom beyond his brief period of experience in the department, stumbles upon an arsonist in the act of torching a Chinese restaurant. This shoot-out sets off a startling chain of events which culminates in murder and high-level police corruption.”