The 79-year-old, who is on remand charged with the murder of Tamworth man Glen Turner, is alleged to have cleared a further 320ha of native vegetation.

The latest claim relates to activities allegedly carried out at the property Strathdoon, about 60km south of Moree, between January and September 2012.

Turnbull’s grandson, Cory Ian Turnbull, owns the property at the centre of the investigation, and is also being prosecuted by the Office of Environment and Heritage (OEH).

In a statement to The Leader, an OEH spokesman said the department launched the case against the Turnbulls on June 25 following an investigation.

“OEH is also investigating other reports regarding the alleged illegal clearing of native vegetation on properties located between Moree and Goondiwindi,” he said.

“As these matters are either still before the courts, or the subject of continuing investigation, it is not appropriate to provide any further comment at this stage.” 

A directions hearing on the new allegations was held in the NSW Land and Environment Court yesterday, where the matter was adjourned.

Turnbull has previously pleaded guilty to illegally clearing 421ha of native vegetation on the property Colorado owned by his son, Grant Wesley Turnbull, and 73ha on Strathdoon.

Video footage shot earlier this week and obtained by The Leader appears to show an excavator conducting more clearing on Colorado.

Ian Robert Turnbull is alleged to have shot Mr Turner – an OEH compliance officer – dead at Croppa Creek on July 29.

The elderly wheat grower is due to reappear in Moree Local Court next month after his application for bail was refused on Tuesday.