ISIS, the militant group that also calls itself the Islamic State, often grabs the attention of the world with shocking videos of beheadings. But it also relies on pro-jihadi songs — called "nasheeds" in Arabic — to spread its message.
"My people, dawn has arrived. Await the expected victory," goes one of the group's best-known songs. It was released at the end of last year, and it has become the soundtrack for so many of the group's videos that some even consider it their anthem.
"It's a pretty catchy song," admits Phillip Smyth, a researcher at the University of Maryland. "Lyrics aside — and the knowledge that the song is representing something very bad for the Middle East — it's a catchy tune."
The lyrics can be almost as graphic as the videos of beheadings. One of them describes how fighters will "crush the skulls of their enemies."
Smyth says it's important to pay attention to these songs. "Narratives that are cast by these groups are usually conveyed in their music first," he says. "Even before official announcements, you'll probably get a clearer picture of what they actually want to promote or what they're going to do through their songs."
ISIS has been churning out song after song, dropping both originals and some borrowed tunes. Smyth says the group uses some familiar Islamic songs that are just re-packaged. "These were religious tunes that people knew and they could go to when they wanted something that was a tad holy and they could identify with," he says.
They might not be originals, he adds, but they serve a key role in outreach to potential recruits.
Smyth uses the example of a student in the West. "Maybe they're a convert to Islam and they want to dabble in this and they're looking for what true Islam means," he says. "The radical groups will try and exploit that and say, 'Look, we even have catchy tunes that can go along with your learning process.'"
At the same time, Smyth says, the songs can also appeal to older people: "They will appeal to nostalgic pieces in their minds."
Putting these songs together also isn't that difficult. Smyth says he once watched a former Christian militia member in Lebanon produce a political song.
"This all occurred in this man's mother's basement," he recalls. "He had a keyboard, he had all of the recording material, a little micro-studio set up. He just picked five guys that he knew to sing the songs and then auto-tuned it — and it was a stirring rendition."
Technology hasn't just made it easier for jihadi groups like ISIS to make music. It has also helped them get around an ideological dilemma: Their strict form of Islam forbids playing musical instruments.
"If they're not allowed, what can you do? Well, using the new technology we have, does that necessarily count as an instrument?" Smyth asks, "If I'm hitting a button on a computer, how does that work?"