HARLEM, Manhattan (PIX11) — In a poignant video posted on Instagram, sixth-grader Alfa Barrie is seen dancing with one of his favorite teachers at Democracy Prep charter school in Harlem, shortly after the new semester started last September.

“Alfa Barrie loved to dance,” the tribute post said on the school’s Instagram. “In this video, you can see Alfa moving swiftly to the beat of the music with his teacher and classmates.”

Cristian Salazar, a spokesman for the school, said the video was recorded at lunchtime last Sept. 21.

This past Saturday, Barrie’s body was discovered in the Hudson River near 102nd Street and Riverside Drive, nine days after he didn’t return to his Bronx home from school.

Two days earlier, the body of Garrett Warren, 13, was pulled from the Harlem River near the Madison Avenue Bridge on the East Side.

Warren was witnessed by another boy pushing Barrie into the Harlem River before slipping and falling in himself, police sources told PIX11 News.

The medical examiner said Saturday the older boy died from accidental drowning, but the office reserved a determination on Barrie’s cause of death until it consults further with detectives.

The two boys were seen in the vicinity of the Harlem River on the evening of May 12, and many are puzzled as to why Barrie’s body was found on the west side of Manhattan Island.

Barrie’s family was planning a memorial in the Bronx for the sixth grader Monday evening.

Democracy Prep will hold a vigil for the student Tuesday. In Monday’s Instagram post, the school noted, “Alfa was someone who was a huge part of his school community — always lending a helping hand to his classmates and teachers, always showing his care and sweetness to his closest friends and family, and always living life with a smile on his face.”

The post continued, “His teachers share that their classroom is not the same since Alfa’s passing. ‘We had a little family; you can tell he is not here.'”

The post concludes, “Alfa is dearly missed and we honor his life by keeping his memory alive. Please join us in extending condolences to Alfa’s family during this difficult time.”