Authorities probably had a very good reason for allowing JonBenet Ramsey murder suspect John Mark Karr to live it up on the 15-hour flight to the United States, legal experts say — they wanted him to talk.

Denver attorney Larry Pozner, past president of the National Association of Criminal Defense Lawyers, said the royal treatment during Sunday's journey — king prawns, champagne, French wine — was "a brilliant move."

"What the cops want most is this guy to talk. They say he is not under arrest. Then they do not put him in handcuffs on the plane. And they say he is over the age of 21, free to drink," Pozner said. "He is therefore free to talk."

If Karr says something incriminating that is challenged in court, Pozner said, the investigator who was sitting next to him simply says he was never in my custody.

"There is always a reason when the unusual happens," Pozner said. "He is in nobody's custody. He is free to leave if he can find a way at 38,000 feet

Karr arrived in Los Angeles late Sunday after boarding a Thai Airways International flight in Bangkok. The 41-year-old teacher sat in a business class window seat next to Mark Spray, an investigator with the Boulder County District Attorney's office.

Before takeoff, he sipped champagne. During dinner, Karr had pate, salad with walnut dressing and fried king prawn with steamed rice and broccoli, followed by a slice of Valrhona chocolate cake for dessert. Karr had a beer before a glass of French chardonnay with the main course.

Karr appeared to order the drinks himself, and instigated conversations with investigators.

A spokeswoman for Boulder prosecutors, Carolyn French, said Karr is being escorted by immigration and customs officials but isn't in federal or Boulder County custody on the flight.

"He's being deported from Thailand because his passport was pulled," French said.

Scott Robinson, a Denver defense attorney who has followed the case, said Karr can enjoy himself on the plane.

"Maybe the whole purpose is to build rapport," he said. "If the click of a glass helps in the search for truth maybe he should click glasses six more times."

Craig Silverman, a former Denver prosecutor familiar with the case, said he was surprised that authorities would allow Karr to sit without handcuffs on the plane, sipping champagne and drinking beer.

"It could be that if he got a little inebriated he would make further statements that could include or exclude him from this case," Silverman said.

Bob Grant, a former Adams County district attorney who was involved in the Ramsey investigation, disagreed.

"It seems odd to me," he said. "It is very strange. Whoever is in control of him ought to make sure he isn't doing things like drinking champagne."