FERGUSON, Mo. — It was 1 a.m. and Michael Brown Jr. called his father, his voice trembling. He had seen something overpowering. In the thick gray clouds that lingered from a passing storm this past June, he made out an angel. And he saw Satan chasing the angel and the angel running into the face of God. Mr. Brown was a prankster, so his father and stepmother chuckled at first.

“No, no, Dad! No!” the elder Mr. Brown remembered his son protesting. “I’m serious.”

And the black teenager from this suburb of St. Louis, who had just graduated from high school, sent his father and stepmother a picture of the sky from his cellphone. “Now I believe,” he told them.

In the weeks afterward, until his shooting death by Darren Wilson, a white police officer, on Aug. 9, they detected a change in him as he spoke seriously about religion and the Bible. He was grappling with life’s mysteries.

Michael Brown, 18, due to be buried on Monday, was no angel, with public records and interviews with friends and family revealing both problems and promise in his young life. Shortly before his encounter with Officer Wilson, the police say he was caught on a security camera stealing a box of cigars, pushing the clerk of a convenience store into a display case. He lived in a community that had rough patches, and he dabbled in drugs and alcohol. He had taken to rapping in recent months, producing lyrics that were by turns contemplative and vulgar. He got into at least one scuffle with a neighbor.