By Soumya Bhamidipati of RNZ

More information about the case of Alexandra's mysteriously appearing milk has come to light, with in-depth analysis of security camera footage revealing who the flavoured milk fanatic could be.

RNZ on Thursday reported on the strange happenings in the small South Island community where, every few days, flavoured milk is left on top of a particular pump at an unattended self-service fuel stop.

Since RNZ's exclusive report, RD Petroleum has reviewed CCTV footage from the MacLean Road site.

Chief executive Craig Fitzgerald said it revealed one likely suspect.

"The main culprit, I believe, is a delivery driver. So he rocks up early in the morning, and later in the evening ... and gets his diesel and leaves his two bottles on top of the pump."

However, the mystery milk man's motive was still unclear.

"We don't know why yet, we've got to talk to him about that," Fitzgerald said

"It's hard to say, because it's not like he's leaving full bottles as a gift, they're sort of half-drunk so I really don't know why he leaves them. Whether he drinks half a bottle of each one and then leaves them there because he doesn't want to take them home for rubbish or whatever, I don't know. It's a bit bizarre."

Fitzgerald would not disclose which company the driver worked for, but said the footage also revealed other possible contenders.

"Some young guys in a car pulled up and got out and put a bottle on the roof of the kiosk," he said.

"If we trawled through the camera footage we'd probably find others, but I think that's probably what's happened - it's started and once word's got out, people are going down and adding theirs to it."

However, he had a stern message for would-be copycats.

"It's been funny and it is a bit of a laugh but just bear in mind that someone's got to get rid of the rubbish, so it'd be good if it could stop."

That someone was a local contractor who kept the fuel stop tidy.

Alexandra resident Poppy Prendergast earlier told RNZ the bottles disappeared within "anywhere from a couple of hours to a full day".

The bottles left included a range of different brands and some were full, while others were half empty. 

Main image (Supplied/Jim Redgrave): Every few days flavoured milk is left on top of a particular pump at RD Petroleum's self-service fuel stop in Alexandra.