''We're a bit concerned that someone's walking around with a high-powered rifle in the middle of the night,'' neighbour Ross McCulloch said.
Over two nights at the weekend, more than 190 hoggets were shot on Peter and Janine Stackhouse's 250ha Hillcrest Farm.
Most were dead when they were discovered on Saturday and Sunday mornings, but some remained alive having been shot in the head, with legs shot off.
It was a ''gut-wrenching'' blow for the Stackhouses and the community had rallied together in support, Mr McCulloch said.
''We're all keeping together to make sure this [offender] can be nailed down,'' he said.
While they would remain on the lookout for any strange vehicles and behaviour, they all hoped the offender or offenders would not return for a third time.
If someone was capable of the ''slaughter'' of almost 200 animals with no apparent motive, Mr McCulloch said it was a concern that they were still at large.
Detective Warren Duncan, of Oamaru, said police had received helpful phone calls from the community, but were appealing for more information.
Given the large scale of the attack, police were keeping an open mind on how many people were involved, he said.
Another neighbour, Fiona Conlan, described the Stackhouse family as ''good neighbours who wouldn't do wrong by anyone''.
''We feel really sorry and gutted for them after what's happened. You just can't understand why anyone would want to do that,'' Mrs Conlan said.
Mrs Conlan was home, about 2km away, at the time of both shootings, but did not hear anything.
Federated Farmers meat and fibre chairman for North Otago Greg Ruddenklau said it was important neighbours looked out for each other and reported suspicious behaviour to police.
Mr Ruddenklau described the large scale attack as a horrible, ''bloodied slaughter''.
''I've never seen anything like this. You often hear about the odd one or two [shot], but usually they just take them for themselves,'' he said.
• A Middlemarch farmer was yesterday gauging interest in setting up a support fund for Mr and Mrs Stackhouse, who had lost $30,000 in potential income.
Declining to be named, but revealing he knew Mr Stackhouse years ago, he said he had approached Rural Women to ''get the wheels in motion to have a whip-round''.
An anti-poaching rural neighbourhood support scheme is in place in the Waitaki Valley, but had not yet been extended to the Ngapara area, Constable Craig Bennett, of Kurow, said.
The anti-poaching initiative, which has support from the Lindis Pass to the Duntroon area, was an effective way to ''shut down'' an area after reports of poaching, Const Bennett said.
Anyone with information should contact Detective Warren Duncan, of Oamaru, on (03) 433-1416 or anonymously via Crimestoppers on 0800 555-111.
