PAPEETE, Tahiti -- When former NBA player Bison Dele and two companions vanished from his luxury catamaran in the South Pacific, investigators faced a major obstacle: they had no idea where the victims disappeared.

Now records from the satellite phone on board are providing some answers.

Police have few clues to go on. No bodies have been found and the only other likely witness -- Dele's brother Miles Dabord -- remains in a coma on life support in a California hospital.

Authorities are tracking the boat's coordinates by studying the satellite phone's calls, investigating judge Jean-Bernard Taliercio said Monday. They are not, however, revealing who was called or what was said -- two key elements under study.

French Polynesian officials have based their work on the suspicion that Dabord, who was traveling with the group, was responsible for the deaths of his brother, his brother's girlfriend Serena Karlan and skipper Bertrand Saldo.

Taliercio said he wasn't ruling out other possibilities, however.

All investigators will say about the catamaran's route is that on July 6 or 7 -- when Dele, his girlfriend and the skipper were last seen -- the boat was sailing near the tiny island of Maiao, west of Tahiti.

Information gleaned from the phone records could be crucial in the case, particularly if Dabord remains in a coma for an extended period and police have no firsthand witness.

Investigators believe the bodies were likely dumped overboard. They are searching in the South Pacific, though they said there is not much hope of finding anything more than 10 weeks after the disappearances.

Dabord has not been charged in the United States in connection with the disappearances. After his companions vanished, he spent about two weeks in French Polynesia before leaving the boat in a Tahiti port and flying home.

Back in the United States, Dabord, who used to be called Kevin Williams, aroused suspicion when he signed his brother's name to try to buy $152,000 worth of gold in Phoenix. He was discovered in a coma in Tijuana, Mexico, on Sept. 14 and was later arrested on suspicion of impersonating his younger brother.

Patricia Phillips, the mother of the two brothers, said Dabord is on life support after overdosing on insulin and failing to take his asthma medicine, the Los Angeles Times reported.

Taliercio said FBI agents told him days ago that Dabord had "very little chance of surviving.''

With chances of Dabord's recovery growing slimmer, a secondhand account from his former girlfriend has taken on added importance.

Erica Weise joined Dabord briefly on the island of Moorea after the disappearances. After returning home, she informed authorities Dabord told her of an onboard struggle that left his companions dead.

Taliercio said authorities were hoping to speak to another person who might have information. He gave no other details except to say the person does not live in the United States or Tahiti and did not witness what happened aboard the boat.

The person has been hesitant to speak to authorities, he said.

The judge also said authorities were considering whether to remove Dele's catamaran from the water for more tests. Authorities believe they found traces of blood on the boat, and Taliercio said DNA tests would be conducted in France, probably in about 10 days.

Dele, 33, changed his name from Brian Williams during an NBA career in which he played for several teams, including the Chicago Bulls' 1996-97 championship team. In 1999, he walked away from a $35 million contract with the Detroit Pistons.

The former athlete had planned to travel to Hawaii from New Zealand.