In early reports of a mass shooting that killed 14 in San Bernardino, California—the U.S.’s deadliest since the massacre at Sandy Hook Elementary School in Newtown, Connecticut, in 2012—eyewitnesses described seeing what they took to be three male shooters fleeing the scene. The facts were more surprising: The shooters were a husband and wife who had dropped off their 6-month-old daughter with her grandmother just hours before the rampage, claiming they had to go to a doctor’s appointment.

Around 96 percent of mass shooters are male, according to the Washington Post, and roughly two-thirds are white, according to a database compiled by Mother Jones; the vast majority, in accordance with stereotypes, are single and have limited ties to family or society. The only female shooter on Mother Jones’ map, Jennifer Sanmarco, had “no family or friends,” as one acquaintance told NBC News.

Investigators are trying to uncover the motives that drove Syed Rizwan Farook, 28, who was American, and Tashfeen Malik, 27, who was Pakistani. San Bernardino Police Chief Jarrod Burguan told the New York Times that he has “not ruled out terrorism”; it’s worth pointing out that terrorists, too, are usually male. We don’t know much about Malik right now. But we do have an abundance of research on why she—as a woman shooter who was also a new mother—is such a statistical anomaly.