Victoria Police is remaining tight-lipped about a series of operations in and around Shepparton in the past few days.
Yesterday, six marked black four-wheel-drives belonging to the Public Order Response unit were seen off Watt Rd, just south of the Watt Rd bridge.
An unmarked police car was also present.
A team of uniformed and plain clothes officers emerged from nearby bushland about 3.30pm, but would not comment on the nature of the investigation.
They were accompanied by a camera crew.
The operation comes following other searches by uniformed police further north along the Goulburn River on Sunday and Monday.
A police helicopter was also operating above the area earlier in the week.
Victoria Police media would not comment regarding the series of searches.