The St. Valentine’s Day Massacre is an iconic piece of American gangster history. Not as much has been known, however, about the assumed gunman behind the incident, Jack McGurn. Now McGurn is the subject of Deadly Valentines, a fast-moving biography by Jeffrey Gusfield. McGurn, whose real name was Vincent Gebardi, was a Sicilian immigrant and professional killer who became Al Capone’s chief assassin. Though he was an immediate suspect in the St. Valentine’s Day Massacre, McGurn managed to elude police for two weeks following the murders. When the authorities found him and his lover, Louise Rolfe, in a downtown Chicago hotel, they claimed to have been in bed on the morning of the famous shootings.

Deadly Valentines, a thoroughly researched story of McGurn and Rolfe, paints a compelling truelife saga of gangland Chicago in the 1920s. Told in the present tense, this is a tale that moves beyond gangsters and guns to bring to light a captivating love affair. This astonishing, entertaining narrative shows how McGurn and Rolfe embodied the excesses of the Roaring Twenties and captured the attention of the public.

Gusfield, a fine art dealer for 30-plus years, is a native Chicagoan who has spent decades investigating the history of McGurn and Rolfe. Deadly Valentines is his first book. Gusfield will appear at Boswell Book Co. on April 10 at 7 p.m.