Barbara Poindexter saw the death of her son coming.

She likens it to watching her mother's health deteriorate. In her son's case, death followed a slow and agonizing descent into gangs and criminal activity.

"When my mother came to the end, I was not surprised," Poindexter said. "When my son came to the end, I was not surprised.

"I just didn't know when."

On May 4, 2012, Quintin Poindexter got out of a car with three men, who were recorded on surveillance video walking behind Windsor Hills Elementary School. Six shots are fired, and Quintin's three companions run back across the frame.

His body was found the next morning by a woman walking her dog.

His family's story offers a window on a struggle among Baltimore families: the tug-of-war between relatives intent on guiding children toward productive lives and criminal organizations in search of recruits.

At the time of his death, relatives and law enforcement authorities say, 18-year-old Quintin was a member of the Black Guerrilla Family gang. Police say he was killed over a missing gun.

"My son was not born a gang member," Barbara Poindexter said. "Someone introduced him to that life, and God forbid, if my son would have lived, he may have introduced someone to that life."

Kyle Williams, 27, pleaded guilty last month to first-degree murder in the killing. He was sentenced to 35 years in prison.

Quintin knew Williams — he had sat at his mother's dinner table, slept in his bed, and played with his younger siblings.

"A fundamental characteristic of gang activity or organized crime," Judge Michael W. Reed said at Williams' sentencing last month, "is often people are killed by people who are known to them or closest to them."

Williams acknowledged that he was present at Quintin's killing but insisted he didn't know what was going to happen.

"It was unfortunate how it all played out," Williams told the judge at his sentencing, as Quintin's family sat a few feet away. Quintin "became a part of something that was vicious."

Quintin was the youngest of four raised by a single mother in Southwest Baltimore. Barbara Poindexter, now 52, worked in health care — working her way up from nursing assistant to owner of two assisted-living facilities — and says she provided a stable home.

For a time, they lived in Baltimore County, where Quintin attended public schools. As a child, his mother says, he was exuberant, inquisitive and obedient.

It was when the family moved back to Baltimore during his middle school years — they landed in the Park Heights area — that Barbara says she began to lose her son.

"His first year in middle school, it was like one person went in, and another came out," she said. Before then, she said, "he didn't know anything about cutting school and smoking weed."

Relatives believe the fatal shooting of one of his best friends in seventh grade was a pivotal moment. He had never been to a funeral before, let alone seen the head of a good friend stapled back together in a casket.

It was an image Quintin could not shake. He stopped going to school. Then he started vanishing altogether, going days without coming home, sometimes dropping in only for family gatherings.