Victorian Jonathan Dick is wanted over the February 2017 murder of his brother, David, in Doncaster and a hammer assault on a man in Keilor five months later.

"It's our belief that over the past year Jonathan has essentially been hiding in plain sight," Victoria Police Homicide Squad head Detective Inspector Tim Day said on Wednesday.

"His movements over the past 18 months are a mystery and we require the public's help.

Police have released video footage of Mr Dick at a friend's wedding last year so members of the public can observe his mannerisms and hear his voice.

Mr Dick also has two distinctive tattoos. One is a Wolverine v Sabre-tooth inking on his right thigh extending to his knee and the second on his left calf depicts the Incredible Hulk.

He is described as being perceived to be of Caucasian appearance, about 176cm tall with a solid build and mousy brown hair.

Police say he is "not a man who stands out".

Australian Associated Press