Nikolas Cruz has been charged with 17 counts of murder after a shooting at his old school, where he had been expelled for "disciplinary reasons".
Fourteen more were wounded at Marjory Stoneman Douglas High School in Parkland, Florida, in one of the worst mass shootings in modern American history.
Cruz's name now joins a roll call of mostly white men attached to the atrocities.
Of 95 mass shootings carried out in the US between 1982 and 2017, 92 of the perpetrators were male.
The final three are made up of two women, and one case of one man and a woman working together, in the San Bernardino attack in December 2015.
The shootings broken down by race, by Statista, show that 54 of the gunmen were white, 16 black, and seven each Latino or Asian.
Although there is frequent speculation about the mental health concerns of those who carry out the devastating acts, there is less conversation around whether the gender of the perpetrator is a larger issue.
Professor David Wilson, a criminologist at Birmingham City University, said: "Characteristics of USA school shooters? Male; used legally owned firearms - usually semi-automatic weapons; were ex students of the school they targeted."
He told Sky News: "What is interesting is that the average gunman tends to be slightly older than we have here [in Florida].
"If you look at the motivation that we know about it does seem to be that men handle their catastrophic loss and self esteem worse than women.
"When the husband or father loses their job or goes through a divorce separation they are thrown out of the home.
"Their status is tied up in their occupation so they seem to suffer more psychologically, which seems to propel them in that way.
"Men also have unequal access to guns and training in using weapons like handguns and rifles.
"Three-quarters of mass murders will use firearms and so that unequal access to the training is relevant."
Professor Wilson added that men tend to have fewer support networks outside the family unit and their workplace, which can be problematic if one of those breaks down.
He said: "Men all over the world have these experiences, but they don't carry out mass murders.
"The reason is that we have different gun laws.