A manhunt is under way after the brutal murder of a Melbourne schoolgirl.
Masa Vukotic, aged 17, was fatally stabbed as she was walking in a park nearby her home in Doncaster, about 7pm on Tuesday.
Police have released security camera footage of a suspect, a man aged in his 20s, seen running in the street nearby Koonung Creek Linear Park in the moments after the stabbing.
A man held by police on Wednesday afternoon, who matched the suspect's description, has been ruled out as having no involvement.
The murder weapon has not been found, and the man in the footage is seen to be carrying a white plastic bag that may have contained it.
Police say the attack appeared to be random though the girl may have been followed in the park, possibly by someone local.
