A ceiling was set on fire and a car damaged by marine flares in incidents being investigated by Oamaru police.
The two incidents in Hampden are believed to be related, Detective Kevin Kirkman said.
Officers called to a house on Chelmsford Street at around 11.50pm on Tuesday found the ceiling on fire.
Police believed the fire was caused by the type of flare commonly used by boaties, he said.
“We also believe a second flare has been launched, landing on a vehicle parked on Chelmsford Street causing damage to the vehicle.”
Police are now seeking any information, including CCTV or dashcam footage.
“We would like to hear from anyone in the wider Chelmsford Street, Derby Street, Nottingham Street, Stafford Street, and Durham Street areas,” he said.
“Specifically between 10.30pm on Tuesday and 1am Wednesday.”
Anyone with information could contact police online at 105.police.govt.nz, or call 105.