Three men who assaulted an elderly Tokoroa couple went to a party afterwards and boasted about what they had done, police say.
The attack last Thursday left 73-year-old Bob Gabolinscy with a gash to his head and his 75-year-old wife Margaret with a black eye and bruising to her face.
The officer in charge of the case, Sergeant Terry Garnett, said three men in their teens and early 20s are believed to have been involved in the attack in an alleyway neighbouring the Gabolinscys' home.
The three are believed to have been at a party in the Balmoral Drive area before the attack, and to have gone on to another party afterwards.
"At the second party they spoke about the incident and we are trying to find some people who could come forward in relation to that.
"What we have heard second-hand is they bragged about what they had done ... I have a funny feeling they didn't have an idea of the severity of what they had done which is why they bragged about it."
Mr Garnett said cans of pre-mixed bourbon and cola the men used to throw at Mr Gabolinscy were fingerprinted. A list of suspects was being checked against the results.
"We are fairly sure we are heading in the right direction but we have to do a bit of homework first," he said.
"Hopefully this should speed things up but sadly we are not CSI whichdoes things in 55 minutes including advertisements."
Mr Gabolinscy did not realise he had suffered a cut to the back of his head during the attack.
Mrs Gabolinscy approached a man who punched her in the right eye, leaving her dazed with blood streaming down her face.
A neighbour found the couple in a state of shock, and they were taken by ambulance to Tokoroa Hospital.
A survey carried out in 2008 on the district's walkways, two years after Mr Gabolinscy featured on the front page of a newspaper wanting the alleyway closed, resulted in four walkways being closed.
But the walkway next to the Gabolinscys' property was not identified as a priority at the time. The South Waikato District Council is now considering closing it.