ALLEN, Texas—The family of Patrick Crusius, the alleged gunman in El Paso’s mass shooting, worried he was a little lost, with few friends, but thought he wasn’t any more aimless than many others his age, said family lawyer Christopher Ayres.

When Mr. Crusius discussed current events, history and politics with his grandfather, with whom he lived for a while, his ideas didn’t appear to be out of the mainstream, according to Mr. Ayres. Like many young men in Texas, he occasionally went to the gun range with his father.

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