グレーターマンチェスター警察 (GMP) said Kennie was found with stab wounds to the chest in Stretford at about 7pm on Saturday.
Four youths aged 15 に 17 were arrested on Saturday before a fifth teenager handed himself in to the station on Sunday, GMP said.
Later on Sunday, a sixth teenager, 高齢者 14, was arrested in Stretford.
On Saturday paramedics treated Kennie at the scene, but he died in hospital of his injuries.
Supt Caroline Hemingway of GMP said on Sunday: “A murder investigation is under way, and a team of detectives from our major incident team have been working through the night and into today to follow up a number of different lines of inquiry, and to piece together the circumstances leading to this callous attack.”
彼女は付け加えた: "再び, we see the utterly devastating consequences of knife crime – it destroys lives, families, and communities.
“It’s so heartbreaking to see such a young life lost, and such young people suspected of being capable of a horrendous act of violence.
“We will not relent in tackling this problem in our society, and we are doing all we can with partners and the community to stop more young lives being lost on our streets.”
GMP has appealed for anyone with information to call 101 or Crimestoppers on 0800 555 111.