A Family of four has vanished without a trace from a tiny community in the Alaskan wilderness. Fox News Shepard Smith talks with investigators. Courtesy Fox News

A FAMILY of four has vanished without a trace from a tiny community in the Alaskan wilderness, leaving police baffled and relatives fearing the worst.

The FBI has been called in to help search for Rebecca Adams, 22, her daughters, five-year-old Michelle Hundley, three-year-old Jaracca Hundley and Rebecca Adams’ boyfriend Brandon Jividen, 37.

The four disappeared from their rented apartment on the scenic Kenai Peninsula, about 250km from Anchorage, in mysterious circumstances more than two weeks ago.

Rebecca Adams last had contact with relatives on May 27, when she made an “ominous” phonecall to her sister and behaved “strangely” during a visit from their mother.

Kenai Police Sergeant Scott McBride told the Peninsula Clarion they were discovered missing on May 31 after relatives, neighbours and the couple’s landlord called officers to ask for a welfare check.

Police found both the couple’s vehicles remain parked outside the four-apartment complex and all of their belongings, including their wallets, clothes, camping gear, childrens’ car seats and Jaracca’s nappy bag were left behind.

The family’s brown and white English springer spaniel “Sparks” is also missing, fuelling speculation they planned their disappearance, or went willingly with another party before meeting with foul play. Their mobile phones have been turned off.

“It looks like they just vanished during breakfast,” neighbour Desiree Guillam told local news site Your Alaska Link.

“Their food was still on the table and the counters and their jackets were on the back of the chairs, Becca’s wallet with her ID and foodstamp card (was) there (and there) was a cellphone and everything.”

Relatives say their last contact with Rebecca Adams, on May 27, was distressing and left them fearing for her welfare.

Lanell Adams told the Alaska Dispatch that she and her sister were planning to chat on Skype when Rebecca Adams called at the last minute to cancel.

The pair were always truthful with each other, Lanell Adams said, and growing up would often say “thou shall not lie” as a way to make the other tell the truth.

Lanell asked Rebecca, “Thou shall not lie — are you OK?”

Rebecca Adams responded, “Don’t ask me that right now. Just know that I love you,” Lanell Adams told the Dispatch.

Concerned, Lanell Adams rang their mother, Jeanine Adams, who went to check on Rebecca.

“(Mum said) It looked like she had been crying,” Lanell Adams said, but Rebecca “just blamed it on hormones or whatever.”

Lanell Adams said her sister’s disappearance was “extremely” out of character and that she was a “very responsible mum”.

But she expressed concern about Mr Jividen, who moved in with Rebecca Adams about two years ago, just weeks after the death of her daughters’ biological father, Jaramiah Hundley, in a motorcycle accident.

Little is known about Mr Jividen except that he is an avid hunter and fisherman and has at least two children from two previous relationships who live in different states.

Landlords Jeff Pfile and Anna Haave told AP they called police after Rebecca Adams and Mr Jividen were late with their rent — a first for the couple.

“If I felt they were going out of town I would have been the first person they called because they are so responsible (for paying their rent on time),” Ms Haave said. “For them to not say anything is not normal.”

A massive hunt involving FBI officers, Alaska search and rescue dogs, local police and volunteers, state trooper helicopters and small planes has been launched in the wooded area surrounding the family’s California Ave home and will continue through until next Monday.

The search area backs on to a jail, Wildwood Correctional Facility, which houses long-term prisoners convicted of serious crimes.

FBI special agent Steve Forrest said “significant resources” had been allocated to the investigation.

“The major reason for our involvement in this particular matter is the age of the children and the mysterious circumstances surrounding their disappearance,” Agent Forrest said.

Lanell Adams, who lives in Washington state, flew to Alaska last week to help with the search.

The Adams family was “afraid,” she said, and had no idea what might have happened.

The family’s baffling disappearance has sparked much rumour and innuendo among residents of Kenai, which has a population of just 7000 but is more transient than close-knit.

There are several theories circulating, including:

● That the family is on the run after falling foul of a drug syndicate;

● That they are marijuana growers who have been kidnapped for their crop;

● That they have been spirited away by government agents to join the witness protection program;

● That they had a family suicide pact;

● That Mr Jividen has kidnapped and murdered his adopted family before killing himself and finally;

● That Mr Jividen is a white supremacist with links to The European Brotherhood and that the group is somehow responsible for their disappearance.

The case has eerie similarities to that of the McStay family, who mysteriously disappeared from their suburban Californian home in February 2010.

Three years later the bodies of Joseph and Summer McStay and their sons, aged three and four, were found buried in the Mojave Desert. The matter remains unsolved.