[Location - Date:PORT ST. JOHN, Fla. -- May 15, 2012][Source:AP; pool][VO:]A MURDER SUICIDE IN PORT ST. JOHN ... FLORIDA TUESDAY ....THE VICTIMS .... FOUR SIBLINGS ... RANGING IN AGE FROM 12 TO 17...THE GUNMAN ... POLICE SAY WAS THE CHILDREN'S MOTHER .. 33-YEAR-OLD TONYA THOMAS.[Notes:SOT Lt. Tod Goodyear, Brevard Co Sheriff's Office: "We know that there have been some domestic issues. There have been some issues with some of the children in the past ... But what precipitated the event this morning, we do not know."]AUTHORITIES SAY THREE OF THE CHILDREN HAD GONE TO A NEIGHBOR'S FRONT DOOR IN THE EARLY MORNING HOURS TO SAY THEY'D BEEN SHOT. THE MOTHER THEN CALLED THE CHILDREN BACK TO THE HOUSE ... AND KILLED THEM.ONE OF THE VICTIMS WAS 15-YEAR-OLD JAX JOHNSON.HIS FRIEND SAYS THE TWO WERE LIKE BROTHERS.[Notes:SOT Malcolm Murray, a friend of 15-year-old victim Jack: "I didn't know she had a gun and I know Jackson didn't either. He even told me. Where this gun came from and where this anger came from ... I have no clue."]POLICE SAY THEY'RE STILL LOOKING INTO A POSSIBLE MOTIVE ... THEY'RE TALKING TO NEIGHBORS ... ONE TOLD THEM HE'D RECEIVED A TEXT MESSAGE FROM THOMAS IN THE MIDDLE OF THE NIGHT ... [Notes:SOT Lt. Tod Goodyear, Brevard Co Sheriff's Office: "The mother advised that she wanted to be cremated with her children. And unfortunately, he did not see that text or read it on his phone until he woke up this morning, which was well after the incident had already occurred."]RECORDS SHOW AUTHORITIES RESPONDED TO FAMILY'S HOME THREE TIMES LAST MONTH... ONE OF THOSE DAYS INCLUDED CHILD WELFARE ... LOOKING INTO ALLEGATIONS OF INADEQUATE SUPERVISION OF THE CHILDREN.[SIGOUT/REPORTER, LOCATION, ASSOCIATED PRESS](****END****) ANCHOR VOICE: Nicole Grether-------------------------VIDEO PRODUCER: Nicole Grether---------------------------VIDEO SOURCE: AP; pool-----------------------VIDEO RESTRICTIONS: none----------------------------------MARKET EMBARGO (S): none--------------------------------SCRIPT/WIRE SOURCE: BC-US--Five Dead-Florida, 8th Ld-Writethru,60