It’s still early, and there may end up being connections between the Tsarnaev brothers and radical Islamic organizations; but the latest information suggests that Islamism may not have been their primary motivation.

An emerging portrait of the brothers accused in the Boston Marathon bombings suggested that the older of the two, Tamerlan Tsarnaev, embraced a more radical form of Islam in recent years.

But scholars cautioned Friday against concluding that the Tsarnaevs’ motives were purely religious. Tamerlan Tsarnaev, who was killed in a firefight with police early Friday morning, appeared to sympathize with Islamic extremists agitating for Chechen independence from Russia.

But family, neighbors, friends, and social media sources painted a complex picture of the brothers’ religiosity.

“The story that seems to be developing here is more along the lines of standard alienated man goes out and commits atrocities, much more like the school shootings we’ve seen than organized Islamic insurgency,” said Yuri Zhukov, a fellow at the Program on Global Society and Security at Harvard University’s Weatherhead Center who studies extremism in the Caucasus.