HPD has confirmed that she called them at 3:30 PM on Christmas Eve. JF was put into the missing person system at 9:30 PM.
Mom must have come home right after the hangup at work. Article (Harris quoted) also states that [Mom's] relatives called LE.
BBM
http://www.chron.com/disp/story.mpl/metropolitan/7356276.html
A few minutes later, the mother arrived home, Harris said. Jonathan was gone, and the cordless phone was missing, he said.
Within an hour, relatives called police, Harris said.
"Patrol responds by like 3:30 p.m. and they're there from 3:30 to 4:15 or so," Harris said.