Detectives from the Homicide Squad arrested the youth at Melbourne Airport on Wednesday morning and charged him with murder to face a children's court the same day.

On March 13 at Reservoir, 16-year-old Declan Cutler was fatally assaulted and stabbed.

Emergency services were called to Elizabeth Street just before 2.30am after reports someone had been assaulted.

Declan was treated by paramedics and police but died at the scene.

Australian Associated Press