IS THE MOST TRAGIC LOSS THEY’VE EVER FACED. DENI: CHRISTIE DIAZ AND HER THREE CHILDREN WERE ON THEIR WAY HOME TO LOUISVILLE AFTER A BIRTHDAY PARTY WHEN THEY WERE HIT ON U.S. 31. >> IT IS A TRAGEDY. DENI: BROKEN GLASS AND DISCARDED CAR PARTS STILL LITTER THIS STRETCH OF DIXIE HIGHWAY, A DAY AFTER A HEAD-ON CRASH CLAIMED THE LIVES OF FOUR PEOPLE. >> SOMETIMES IT TAKES EIGHT WEEKS, BUT WE WILL GET SOME ANSWERS. DENI: KSP TROOPER SCOTTY SHARP SAYS 52-YEAR-OLD SYNTHIA ARMSTRONG WAS DRIVING SOUTHBOUND WITH A 7-WEEK-OLD BABY WHEN SHE CROSSED THE CENTER LINE AND HIT CHRISTI DIAZ’S CAR. ARMSTRONG WAS KILLED BUT THE INFANT SURVIVED. >> THANK GOODNESS IT WAS NOT INJURED, BUT WAS STILL TAKEN TO NORTON CHILDREN’S HOSPITAL TO BE CHECKED OUT. DENI: DIAZ AND TWO OF HER CHILDREN, 14-YEAR-OLD JOSHUA AND 12-YEAR-OLD MACKENZIE, WERE ALSO KILLED. DIAZ’S 11-YEAR-OLD SON SURVIVED THE IMPACT AND WAS ABLE TO CLIMB OUT OF THE CAR. HE WAS TAKEN TO THE HOSPITAL WITH SEVERAL BROKEN BONES. SHARP SAYS KSP SPENT MORE THAN SIX HOURS RECONSTRUCTING THE CRASH. >> USED A SOFTWARE PROGRAM THAT PUTS THAT TOGETHER, PIECES IT, SO THAT PEOPLE CAN VISUALIZE WHAT OCCURRED, ALONG WITH PICTURES THAT WERE TAKEN. DENI: FAMILY MEMBERS SAY DIAZ WAS A DEVOTED MOTHER WHO HAD JUST TURNED 44. JOSHUA LOVED BASKETBALL AND HAD JUST FINISHED UP HIS FRESHMAN YEAR OF HIGH SCHOOL. THEY SAY MACKENZIE WAS HEADING INTO 8TH GRADE AND WAS FULL OF SPARK. SHARP SAYS THE CAUSE OF THE CRASH IS STILL UNDER INVESTIGATION. >> AND OUR HEARTS GO OUT T