By Barbara Liston

ORLANDO, Fla (Reuters) - Two-year-old Caylee Marie Anthony probably died of suffocation from duct tape wrapped three times around her head at the nose and mouth, prosecutor Linda Drane Burdick said on Tuesday.

She spoke at the opening of the first-degree murder trial of Casey Marie Anthony, the 25-year-old mother of Caylee.

"The only evidence indicating the cause of death of Caylee Marie Anthony are the three pieces of duct tape covering her nose and mouth," Burdick said in her opening statement.

Defense attorney Jose Baez disputed the prosecutor's version when he spoke after Burdick.

"She never was missing. Caylee died on June 16 when she drowned in her family's (swimming) pool," Baez said.

Casey Anthony is charged with murdering her daughter and then hiding her body in woods near her home. Prosecutors took most of their opening statement to outline an elaborate web of lies they said Anthony created.

A photo of the last picture taken of Caylee coloring a picture on Father's Day June 15, 2008 was displayed for the jurors by Burdick on a split screen monitor. On the other half of the monitor, Burdick flashed for a short time a crime scene picture of Caylee's skull and bones where they were found in December 2008 in the woods a short walk from the Anthony home.

Burdick provided jurors with a timeline of events since Caylee was last seen alive by her grandfather, George Anthony, on June 16 at 12:50 p.m. He kissed Caylee goodbye on the little girl's way out the door with Casey Anthony.

On that day, Casey Anthony was dressed as usual for work at Universal Studios theme park where her parents believed she had worked for years. But cell phone records show that Casey did not leave the area of the house that the three generations of Anthonys shared until 4 p.m.

More than a month later, during a missing person search for Caylee, two different cadaver dogs brought to the Anthony home detected the odor of human composition near Caylee's backyard playhouse.

After the investigation began into Caylee's disappearance, investigators also determined Casey had not worked at Universal since her maternity leave almost three years earlier despite dressing in her Universal work clothes, carrying a Universal identification card and fooling her family.

Burdick outlined a series of lies that she said Casey told her mother Cindy Anthony and friends after Caylee's disappearance.

At various times, Casey claimed Caylee was being watched by a series of babysitters, that Caylee had gone to a business meeting with Casey at Busch Gardens theme park in Tampa, that Caylee had gone with her to Jacksonville, that Caylee was at the beach and at a cartoon character breakfast at Universal, Burdick said.

All this time, security cameras at Orlando shopping malls and stores placed Casey in town and without her daughter. Friends photographed Casey the week after her daughter's disappearance participating in a "hot body contest" at a nightclub, the prosecution alleged.

Cell phone records indicated she spent nights at a boyfriend's house when her parents thought she and Caylee were out of town.

The facade began unraveling when George and Cindy Anthony found Casey's car at an impound lot and Cindy famously told police in a 9-1-1 call that the trunk "smelled like a dead body," Burdick said.

The story line of Caylee Anthony's death is so bizarre that the case has received nationwide publicity. Spectators began arriving before dawn for one of the 50 seats reserved for the public on the opening day of the trial.

"It touched my heart from the beginning. I wanted to see it through," said Bev Robinson, a 74-year-old retiree from Orlando, who arrived at 4 a.m. to get a seat.

(Editing by Greg McCune)