A pensioner was shot five times in the arms and legs after masked men broke into his home in Coleraine, the PSNI said.
Police said they received a report of a shooting incident on Thursday evening.
A number of men wearing balaclavas broke into a house in the Ballgallin Park area of the town shortly before 8pm and assaulted the man aged in his 70s.
In a statement, a spokesman for the PSNI warned against “vigilantism”.
“When the man was taken to hospital for treatment, it was established that he had been shot five times in the arm and legs. He had also sustained injuries to his head and torso.
“At this time, the injuries he received are thankfully not thought to be life-threatening.
“It’s absolutely appalling that an elderly person should be attacked in their own home in this way. There is no place in our society for vigilantism and we are fortunate that the outcome was not much more serious.
“Our enquiries are at an early stage and we would appeal for anyone with information in relation to this incident to contact us.
“If you saw or heard anything suspicious, or have CCTV or other footage which could assist our investigation, please call our detectives who can be contacted on 101.”
You can also submit a report online using the non-emergency reporting form or information can be given anonymously through the independent charity Crimestoppers on 0800 555 111.