SAN DIEGO - A family member told 10News that the remains of Joseph and Summer McStay were found in San Bernardino County earlier this week.
However, Patrick McStay, father of Joseph McStay, did not disclose any information regarding the couple's two young sons, Joseph Junior and Gianni.
The McStay family, from Fallbrook, has been missing since 2010.
Early Thursday evening, sources said investigators were looking into the possibility that the remains of four people found in the Mojave Desert near Victorville are those of the McStay family.
10News learned a San Bernardino County sheriff's detective met with a relative of the missing family Thursday afternoon, but the details of that meeting were not disclosed.
San Bernardino County sheriff's investigators are continuing their probe and have not confirmed any identities. Authorities will hold a press conference about the investigation at 11 a.m.
On Monday, the San Bernardino County Sheriff's Department said a motorcyclist reported finding bones in the Mojave Desert near Victorville, 60 miles northeast of Los Angeles. Investigators confirmed that the remains were human.
Sheriff's investigators also confirmed at least two shallow graves with skeletal remains in it were found, as well as skeletal remains near the graves. No evidence was found at a third gravesite, sheriff's investigators said.
Sheriff's investigators said the remains of four people were recovered and will be analyzed by medical examiners to determine the causes of death, ages and gender.
The San Bernardino Sheriff's Department said it appeared the remains have been in the area for a long time.
Authorities said Joseph McStay, his wife Summer and their two young sons Joseph and Gianni, disappeared from their Fallbrook home on Feb. 4, 2010. There were no signs of a struggle and no signs that the couple had financial problems. Their two dogs were left unattended, and it was not until after neighbors complained about barking that family members and investigators realized the McStays had vanished.
The family's SUV was found days later near the border crossing in San Ysidro, and when investigators checked surveillance video, they saw dark images of what appeared to be the family walking into Mexico.
However, several leads in Mexico later proved to be unfounded.
The effort to find the McStays went national, including a profile on the show "America's Most Wanted" several months after they were reported missing.
Multiple theories have been raised regarding the family's disappearance, including one author's belief that Summer McStay killed her husband and fled with their children.
Earlier this year, the San Diego County Sheriff's Department said their investigation was handed over to the FBI.
LATEST: Sheriff confirms remains of McStay family found; Father of Joseph McStay angry about handling of case: http://bit.ly/HXqAWh
Father of missing McStay dad speaks to 10News: http://bit.ly/1aXV9qH
Shocking new theory about McStay family disappearance: http://bit.ly/18AOs8f
SD Sheriff's Dept. hands over McStay family case to FBI: http://bit.ly/1dzlMjH
Missing McStay family on America's Most Wanted: http://bit.ly/1iglFgr
New clues uncovered in disappearance of McStay family: http://bit.ly/1e8ei89