The "outstanding" work of a local police officer who recognised a distinctive cap and T-shirt from the scene of Aiia Maasarwe's death led to the early arrest of murder suspect Codey Herrmann.

But a massive political glitch could have jeopardised the initial homicide investigation.

Mr Herrmann's arrest came two days after the student's death when a police officer stationed at Heidelberg recognised a "1986" cap and two-tone grey T-shirt left outside the shopping centre where Ms Maasarwe's body was found.

He has been charged with the rape and murder of the exchange student, a Palestinian citizen of Israel, who was killed shortly after she left a tram in Bundoora last Wednesday.

Mr Herrmann was on bail for minor offences.