It could be weeks before the results of an investigation into Saturday's deadly boat crash on Lake Lanier are available.

Melissa Cummings, spokeswoman for the Georgia Department of Natural Resources, said a team began reconstructing the collision Sunday.

It's not yet clear what caused the two boats to collide, injuring several people and tossing 14-year-old Trevor Jones of Buford into the lake, where he drowned.

Officials haven't determined if the boats' occupants were wearing life vests, Cummings said. No charges have been filed.

Emergency workers from Dawson, Forsyth, Hall and Lumpkin counties responded to the call about 7 p.m. Saturday near Toto Creek Park at the Dawson-Hall county line.

Dawson County Emergency Services Director Billy Thurmond said a nearby resident heard screaming and called 911.

"The caller said two boats had collided and that the boats were pulling kids," said Thurmond, citing the 911 report.

According to witnesses who live along the major channel, one boat was carrying a driver and a spotter, who was watching a skier being pulled behind it.

The witnesses said the second boat, in which Jones was a passenger, was pulling several children on two inner tubes.

In all, there were 15 people aboard the vessels.

Two of the other injured, including 13-year-old Kaitlyn Smith of Social Circle, were taken to Atlanta area hospitals.

Smith was flown in critical but stable condition to Children's Healthcare of Atlanta Scottish Rite with internal injuries, Thurmond said.

Jack Struve, 57, of Cumming suffered moderate injuries to his face and was taken to North Fulton Hospital in Roswell.

Cummings said Jones, Smith and Struve were on the same boat.

Rescuers from several agencies started searching for the missing teen Saturday night.

Those efforts were called off after dark, though emergency personnel remained at the scene until after 11 p.m., said Greg Rowan, commander of the Dawson County Sheriff's dive team.

Rowan said the team's sonar unit, which is designed to detect underwater objects, allowed rescuers to mark locations near the site to resume the search early Sunday.

Dawson County Emergency Service's K-9 Strike team also took part in the search.

Dive teams from Dawson and Hall counties recovered Jones' body just after 1 p.m. Sunday.

Several agencies assisted with the search, including Forsyth County authorities and the U.S. Army Corps of Engineers.

Chaplains from the DNR and the Dawson sheriff's office were on the scene to comfort members of the teen's family.

So far this year, Lake Lanier has had nine drownings and six deaths resulting from boating incidents, Cummings said.

An online memorial page said Jones was a freshman at Buford High School and previously lived in Loganville. As of Tuesday, funeral services were incomplete.

Jeff Gill of the DCN regional staff contributed to this report.