When Tashfeen Malik, along with her husband Syed Farook, killed 14 people in San Bernardino a year ago, she provided a stark reminder about the growing involvement of women in jihadist terrorism in the West. Since the attack, women have continued to advance jihadi efforts in the United States and abroad. While few follow in Malik’s footsteps and pursue violent plots, many disseminate propaganda, donate resources, or travel abroad to support jihadist groups, and the numbers are on the rise.

In the decade following 9/11, only a handful of cases, like those of Aafia Siddiqui and Colleen LaRose, highlighted the threat female jihadists could pose to national security. Since 2011, however, instances of terrorism-related activity perpetrated by women have increased.

In a recent report for the George Washington University’s Program on Extremism, we assessed the current escalation in activity by examining the cases of 25 jihadi women in the United States from January 2011 to September 2016. The cases offer a tremendous diversity of demographic data, suggesting it is impossible to discern an overarching profile of the American female jihadi. The individuals hail from 14 states, range in age from 15 to 44 years, and aligned themselves with a variety of organizations, including al-Shabaab, the Taliban, al-Qaeda, and the Islamic State.

The cases offer a tremendous diversity of demographic data, suggesting it is impossible to discern an overarching profile of the American female jihadi.

The study also finds that women’s contributions, both aspirational and achieved, fall into three overlapping categories: plotters, supporters, and travelers.

The plotters design, attempt, or carry out domestic attacks. Asia Siddiqui and Noelle Velentzas, for example, were arrested in April 2015 for conspiring to prepare an explosive device to be detonated in a terrorist attack in the United States. According to legal documents, the two women researched and acquired the necessary materials to create improvised explosive devices by studying chemistry books, The Anarchist Cookbook, and instructions in online jihadi publications. Prior to their arrest, Velentzas reportedly carried a knife in her bra and Siddiqui possessed multiple propane gas tanks, as well as instructions for how to transform propane tanks into explosive devices. Even though few female jihadis in America assume roles as plotters, they are a dangerous segment of the larger movement.

The supporters are less directly operational, choosing instead to garner resources within U.S. borders, disseminate propaganda, or conceal information about impending threats to advance the agenda of jihadi groups. In July 2014, authorities arrested Muna Jama in Virginia and Hinda Dhirane in Washington on charges of providing material support to al-Shabaab. According to legal documents, the women participated in an elaborate scheme to transmit funds to al-Shabaab facilitators in Kenya and Somalia. Jama, Dhirane, and several of their co-conspirators used coded language to disguise their fundraising efforts: the terms “orphans” and “the family” referred to al-Shabaab, while “living expenses” meant money collected for the organization. Supporters make up a significant portion of jihadist activity by women in America, in part because it is the easiest form of contribution.

The final category we identified, the travelers, migrate to participate in the movement directly. They fulfill roles such as raising the next generation of jihadis, disseminating propaganda, and providing medical care. In some instances, organizations herald women’s participation as a means to recruit men with the promise of companionship.

Among this group is Nicole Mansfield, who likely traveled to Syria in 2013, prior to the official declaration of the self-proclaimed caliphate. Although accounts of her death and involvement vary, a comprehensive report suggests that Syrian government forces killed Mansfield after she allegedly tossed a grenade at them.

In another case, Jaelyn Young and Muhammad Dakhlalla, a couple from Mississippi, spent several months planning to travel to Islamic State-held territory and communicated step-by-step details online with two undercover FBI employees. In one interaction, Young told the undercover agents that the duo would travel to the region under the guise of newlyweds on a honeymoon. Young wanted to provide medical aid and embraced her future role as a wife, community member, and mother in Islamic State-held territory. On August 8, 2015, officials arrested Young and Dakhlalla at Mississippi’s Golden Triangle Regional Airport after they confessed to their attempt to join the Islamic State.

Social media platforms are an especially common medium through which women become active, allowing them to disseminate propaganda and make new connections with like-minded jihadis.

Despite the natural inclination to assign levels of severity to the three different categories, doing so would be counterproductive given that women can contribute to jihadi efforts without perpetrating violence. Social media platforms are an especially common medium through which women become active, allowing them to disseminate propaganda and make new connections with like-minded jihadis. Much like broader radicalization and recruitment trends, individuals from all three categories use social media platforms, suggesting that online and offline dynamics complement one another and remain influential among female jihadists. (Their use of this medium also provides an opportunity for law enforcement, as it can be exploited for the purposes of online detection and disruption.)

These findings do not chart a clear path forward, but the efforts of female jihadis in America, similar to their male counterparts, must be met with a varied response. While the vigilance of law enforcement is vital, the legal system is not apt to process all sympathizers, particularly in instances where women advance the ideology without breaking any laws. Women often traverse this liminal space and policymakers need to take them seriously. In addition to legal actions, such as prosecution and incarceration, complementary strategies are also necessary. Just as narratives of Islamic State fighters who have defected from the group have been promoted to deter recruitment, the narratives of women offer unique perspectives for countering violent extremism. The United States should offer alternatives to arrest, explore de-radicalization, and emphasize prevention to respond to the diverse and increasing involvement of women in terrorism.