Authorities continued searching Friday for a woman missing since Monday, when her 3-year-old scratched and bloodied son turned up at a store parking lot 12 miles from their home and said she had been killed.
Sheriff Ken Furlong said he remains hopeful that Bertha Anguiano, 33, of Carson City, is alive and with Juan Carlos Tellez, named by the boy as the man who hit him and his mother and pushed them from a truck.
Furlong also said investigators learned Anguiano had a relationship with Tellez, 36, that had been going on for several weeks despite her husband's demand that she stop seeing him, and it's possible she left willingly with Tellez.
"I'm hoping there are (together)," Furlong said. "I dread the thought that they are not together." He added that one witness told authorities that Tellez, a laborer with no fixed address, has a propensity for violence.
The sheriff also said he thinks Tellez and Anguiano are still in this area, although authorities in Salt Lake City, where the man has family, have been notified. The FBI and police in Southern California also are involved in the case.
"I believe he's somewhere in the northern Nevada area," Furlong said. "I believe we will have contact with him. I'm hopeful that when we do, we can reach her."
More than 100 officers have been involved in the investigation and search efforts that began Monday after the woman's son, Andrew, was found in Dayton, a small town on U.S. 50 in the desert east of Carson City.
On Thursday, the sheriff questioned the boy's statement that his mother was killed, saying the boy "probably doesn't have the ability to recognize death and consciousness at this point."
The missing woman's husband, Filiberto, 32, initially withheld information about a heated confrontation he had with his wife over Tellez, Furlong said, adding that the husband has since been cooperative and isn't a suspect.
While the sheriff said he's hopeful the woman is alive, searchers continued looking in remote areas around Dayton where a body might be dumped. Investigators are still awaiting results of lab tests to determine whose blood was on the boy's shoes and socks.
The boy was found about 90 minutes after he left his home with his mother to drop off another brother at school. The mother's car was found at the school, but her keys, purse and about $3,700 in weekend receipts from the family's video rental store were missing.