A family remains in hiding after being threatened in their home at gunpoint and told to pay up to $1 million.

Four balaclava-clad offenders forced entry to a Keilor Downs home, in Melbourne’s north-west, about 2am on April 20.

Three occupants – a 62-year-old man, 54-year-old woman and 17-year-old girl – were corralled into a room and had their heads covered with blankets.

The offenders, believed to have been armed with firearms and a sledgehammer, rifled through the house and stole a number of items, including jewellery.

They also threatened to return if up to $1 million in cash was not paid by a deadline, police said.

The occupants were not physically injured during the ordeal, which lasted about two hours, with the offenders leaving shortly after 4am.

Detective Senior Sergeant Jason Connor said the “horrifying” targeted attack had left the family traumatised.

“Triple-zero wasn’t contacted,” he told reporters on Monday.

“The victims were so frightened by the demands and the incident that they reported it a few days later due to fear of reprisal.”

The trio has moved out of the home and is in hiding, Connor said.

Police are investigating the reason the family was targeted, but believe it was due to a business deal or perceived debt.

Connor said their family business was involved in the purchase of jewellery and police did not believe they owed any money.

“It’s just an avenue that we’re exploring whether it’s a business deal gone sour or not,” he said.

With lines of inquiry “exhausted”, police on Monday released digital composite images of two men wanted over the attack, along with CCTV of a vehicle of interest.

“We’re adamant there are people out there that will know the identity of the two people we’ve released images of today,” Connor said.

“We’re conducting a thorough investigation of this violent incident, and it won’t be long until we come knocking on doors and making arrests.”

The stolen property has not been recovered as police continue to investigate whether the armed offenders were hired.

–AAP