Barbara and Terry Mann were supposed to complete their adoption of 20-month-old Anthony Lamb on Thursday. Instead, they had to plan funerals for him, their daughter, three other adopted children and two nieces.

All died in a fiery wreck Wednesday in this close-knit north Florida town of about 2,000 people. After hearing of the accident, Barbara's father was overcome by grief, had a heart attack and died.

"It's hard to fathom what it's like to lose five children, two nieces and a father in one shot. It seems like a burden too big to bear," said Scott Fisher, a family spokesman and pastor at the Lake Butler Church of Christ.

Friends and family gathered to mourn their deaths as investigators tried to piece together how the three-vehicle accident happened on a clear day on a road free of obstructions. A semi truck failed to stop and slammed the children's car into a school bus that was dropping off students in front of it, authorities said.

The car burst into flames, charring the bodies. Everyone in the car was killed, including the 15-year-old Nicky Mann, who was driving illegally and was apparently picking up her adopted siblings from school. Three children on the bus were seriously injured.

Along with Nicky, who was the Manns' biological child, and young Anthony, the other victims were identified by authorities and friends as three children adopted by the Manns — Elizabeth Mann, 15; Johnny Mann, 13; and Heaven Mann, 3 — and their nieces, Ashley Keen, 13, and Miranda Finn, 8. The victims had originally been identified by authorities as seven adopted siblings.

The Manns were known as a loving family who constantly opened their home to foster children.

"The children that went to the Manns' home and stayed at the Manns' home did well," said Nia Weeks, a liasion with foster parents for Partnership for Strong Families, a private agency that handles foster care in the area.

"They wanted 10 children," said Wanda Lewis, director of children at Fellowship Baptist Church in Raiford. "They just had a heart for the love of children that no one else wanted, the ones that no one else would have taken."

"If foster care called them it didn't matter what time of night it was when they got called, they were always willing to take them," said Tammy Griffins, the church's student ministry director.

Johnny, Elizabeth and Heaven also came from foster care, she said. Heaven was adopted a month ago.

Both women got to know the children at the church, which they attended three times a week.

Nicky was "just a fun, loving, caring girl," said Lewis, noting that she doted on her adopted siblings. "She did everything for them, changed their diapers. She was the mother hen."

Heaven "was a talker, she could put you in your place," Lewis said.

"Johnny was a wonderful little boy. Very energetic. He loved to play touch football," while Elizabeth was quieter, Griffins said.

One classmate said "she didn't know how she was going make it without getting her hug from Elizabeth every morning," Griffins said.

Bob Peeling, a guidance counselor at Lake Butler Middle School, said Wednesday was Ashley's first day at the school because she had just transferred there.

The children's relatives declined to talk with The Associated Press. But Tina Mann told CNN that her niece Nicky, who had a learner's permit, had dropped off another child and was taking her siblings home "to get ready to go to church."

"Even though she was an underage driver, it's my understanding she did not cause the accident," Mann told CNN. "The same thing would have happened had there been an adult in the car with her. We'd just have one more death in the family."

Tara Brown, a 10th grader at Lake Butler High School, said Nicky Mann was her best friend and that she came to the school to pick up the children every day.

Charges were pending against the 31-year-old truck driver, Alvin Wilkerson. The Jacksonville resident suffered minor injuries. There was no answer Thursday at phone listings for him.

Preliminary evidence shows that stop signs and all the safety measures were working properly on the bus, said David Rayburn of the National Transportation Safety Board. A video recorder was apparently on the bus, but it wasn't working, he said.

The Florida Highway Patrol initially reported that there were no brake marks from the truck on the highway. But Rayburn said there "could've been some light braking marks," although investigators hadn't determined that yet.

The highway is straight and flat in the area, with a paved shoulder on each side. Nothing blocked the view and the weather was clear at the time. Four fatal crashes have occurred in that part of the road over the past five years, FHP Lt. Mike Burroughs said.

Authorities were looking into whether Wilkerson was possibly talking on his cell phone, if he was tired or if there was a mechanical failure of the truck, Burroughs said. Burroughs said a sample of Wilkerson's blood-alcohol level has also been collected.

Wilkerson's commercial driver's license was valid, according to the state Department of Highway Safety and Motor Vehicles. He was cited in 2000 for driving with a suspended license and was twice cited for operating a vehicle in unsafe condition in 2000 and 2001, although details were not immediately available, according to state officials.

The truck's owner, Crete Carrier Corp. of Lincoln, Neb., was cooperating with investigators, but it couldn't discuss the accident, said Jack Peetz, executive vice president and chief operating officer.

All nine students on the bus were taken to hospitals. Three were in serious condition and two were in good condition, hospital officials said Thursday. The rest were treated and released. The bus driver, Lillie Mae Perry, was in stable condition, hospital officials said.

Dalton Sumner, an 11-year-old boy who was on the bus, said he heard the semi honking its horn before the crash, which spun the bus around.

"We just went into the ditch and hit a tree," he told reporters at a Gainesville hospital. "I walked off the bus and I was walking around for a little while. I got on my knees and laid down, and I remember that I couldn't move."

But he said the he later felt fine and a doctor said he was to be released later Thursday.

Grief counselors and others were on hand Thursday to help students deal with the tragedy in Lake Butler, which is about 60 miles southwest of Jacksonville.

"We're just talking about all the good times we had with them. And just trying to remember all that. They're just in such shock," Griffins said.