Ross Streeter was arrested just after 11.30am on Saturday.

Police were called to a house on Cambridge Street in Avoca after Rural Ambulance received a call to attend a man with self-inflicted injuries.

The 30-year-old was taken into police custody and transported to the Royal Melbourne Hospital with non life-threatening injuries.

A Royal Melbourne Hospital spokeswoman said the man was in a stable condition.

Ross Streeter is Douglas' son.

According to Streeter's Facebook page, he finished his education in Maryborough, Queensland, and has a young daughter. On August 12, a picture was uploaded to his page showing Streeter, his father and a woman in an embrace.

Homicide squad detectives and SES spent most of today poring through rubbish at VATMI Recycling in Bendigo East, in the search for evidence relating to the double murder.

The site became an area of interest yesterday when a wallet belonging to victim John Streeter was found by a staff member.

Other items have been discovered by the homicide squad at the plant this morning and will be subject to forensic analysis.

The investigation into the murder of brothers John and Douglas Streeter is ongoing.

The pair, both in their 60s, were found dead at their Natte Yallock sheep farm on Thursday. Both were believed to have died from gunshot wounds.

Detective sergeant Sol Solomon said it was an "extremely lucky break" an employee at the VATMI recycling plant had found John Streeter's wallet.

"He found the wallet and was in the process of trying to track the person down when he recognised the address on the driver's license and had heard the news," he said.

The wallet was believed to have been taken from the victim after the murder and dumped in a bin somewhere between the crime scene and the Bendigo area, Detective Solomon said.

He would not say what other items had been discovered at the recycling plant on Saturday.

On Friday a number of people were questioned, but none were treated as suspects, Detective Solomon said.

He said there were still no clues as to the motive behind the killings.

"From all accounts the two victims were highly respected citizens of the area," he said. "It's an absolute tragedy for their families and the community of Avoca."

Detective Sergeant Solomon said police wanted to speak to anyone who might have been driving near to Moyreisk-Natte Yallock Road or Natte Yallock-Moonambel Road between 8am and midday on Thursday, about 90 kilometres north of Ballarat

- with theage.com.au