Andrew Caballeiro was just one week old when he was abducted.
The FBI have joined the search for two-week-old Andrew Caballeiro.
The newborn went missing last Wednesday along with his father, 49-year-old Ernesto Caballeiro, who was later that day found dead via self-inflicted gunshot wound.
The search for the two began when police discovered the bodies of three women at their Miami home; they were later identified as the baby's 40-year-old mother Arlety García Valdés, 60-year-old grandmother Isabel Valdés González, and 84-year-old great-grandmother Lina González Licor.
Investigators suspect Ernesto Caballeiro murdered all three before killing himself.
"Our detectives are still following all the leads they have in the case," Miami-Dade county police Detective Ángel Rodríguez told el Nuevo Herald. "We have the assistance of the Florida Department of Law Enforcement and the FBI, but at this time there's been no change in the investigation."
A video showed Ernesto leaving the house with his son, but when police located his van in a wooded area 220 miles away in Pasco County, there was no sign of the baby. Officers said they found a pacifier, but no car seat.
"After we swabbed it for forensics we did a search, we had the bloodhounds out there searching -- the bloodhounds hit nothing," Pasco County Sheriff Chris Nocco said at the time. "There was no indication the child was in the area."
Sheriff Nocco also revealed a witness reported spotting a blonde woman sitting in the van earlier in the day. "I sit here and pray to God that that is true, and that she has the baby," the Sheriff said.
"If that is a true fact and that woman is out there: please come forward. I promise you that all we care about is that little Andrew is okay."