Search for Father's Day Vic murder clues

Police and SES crews are trawling Victoria's Mornington Peninsula for clues after a fatal Father's Day shooting.

The search is focused on an area in Dromana on the Victorian coast, near where 31-year-old Joshua DiPietro was shot and killed in a car at Rosebud on Sunday.

An SES spokesman told AAP on Thursday a crew from Sorrento was at the scene with police but he was not able to comment on the nature of the search.

News Corp has reported investigators are looking for a weapon.

Mr DiPietro was shot in the head in a car on Sunday night after spending Father's Day with his parents in Rosebud.

He was dropped off at a milk bar in Rye by his mother, who kissed him goodbye and told him she loved him.

He was collected by a friend and police believe the pair was headed to the RSL for a drink when Mr DiPietro was shot.

"We certainly believe this was a targeted attack, it was very specific: shots fired into the car," Detective Inspector Mick Hughes said previously.

The search comes after an associate of Mr DiPetro was arrested after a 10-hour-long police stand off in Rosebud on Monday.