In the weeks before he was fatally shot in the hallway of a North End apartment building, 15-year-old Keon Huff Jr. had twice been reported missing and was no longer enrolled in city schools.

Police are now working with state agencies to construct a timeline of their involvement with Keon, according to Hartford police Deputy Chief Brian Foley. The state Department of Children and Families is examining Keon's case and the Office of the Child Advocate also is conducting a review.

"I think all of us have to re-examine our efforts," Martha Stone, an attorney who has represented Keon for the past three and a half years, said Monday. "You can always say: 'Is there anything else we could have done?' and I think that's an important question for all us."

On March 2 and March 10, Keon was reported missing by Hartford police, according to public advisories known as Silver Alerts that are often issued for runaways and at-risk individuals.

Hartford school officials said Monday that he was enrolled as a 10th-grade student at Journalism and Media Academy from late September through early February. It was not clear late Monday why he was no longer attending city schools.

Hartford police said Monday they are continuing to investigate the homicide, including looking back at any past interactions they had with the boy. Hartford police have yet to say publicly what may have motivated the killing.

Keon, the eighth person to be killed in Hartford this year, was found with a gunshot wound to the head Friday night in the rear hallway of a Garden Street apartment building.

The adults who counseled and coached him described a resilient young man and strong athlete, prone to fits of anger but always willing to cool down and come back for another talking-to or another basketball game. He was an "overcomer" and had great potential, said Keon's mentor and basketball coach, Dean Jones.

But for all the opportunities that came his way, Keon would not stay out of the streets, Jones said.

"He had a very difficult life and a lot of us surrounded him," Stone said. "A lot of people tried to help him."

Police Chief James Rovella, who attended a vigil Sunday evening for the slain teen, said: "I can tell you that drugs are tearing at the foundation of our families ... Kids between 10 and 15 out here, they have seen more than people 25 to 30 years old in the suburbs ... Life is different here, and we all need to do better."

Officials acknowledge the teen had involvement with a number of community individuals and organizations from the YMCA in Hartford to Mayor Luke Bronin himself.

In a statement released after Keon's death, Bronin said, "Keon was in direct contact with many of our close community partners, who were trying hard to mentor him and get him the support he needed. But as a society, we're failing too many young men like Keon. Between state agencies, courts, schools, police, and community organizations, we need to figure out a better way to work together."