INDIANTOWN, Fla. (AP) _ It must have seemed like a foolproof plan to a convicted sex offender desperate to be free: A helicopter swooping down to rescue him, more than $10,000 in cash and a van ready for a getaway.

But 28-year-old Steven Whitsett's hopes were dashed Tuesday when authorities found him and his alleged student pilot accomplice plodding through waist-high canal water, their clothes soggy and muddy.

The convict and 23-year-old Clifford Burkhart, captured after more than 24 hours on the loose, were scheduled to appear in court today for the first time since their daring escape attempt.

On Monday, Burkhart's rented chopper landed on the grounds of the Martin Treatment Center, picked up Whitsett and cleared a 15-foot razor-wire fence, police said.

It crashed near an orange grove only 100 yards away. Whitsett and Burkhart ran off into the surrounding swamp, leaving behind empty gun holsters, police said.

Authorities had combed a five-by-nine-mile area of orange groves, forests and mosquito-ridden swamp near the treatment center, about 35 miles from West Palm Beach.

On Tuesday, a deputy spotted Whitesett and Burkhart walking in a canal near a gated subdivision in Stuart and fired two warning shots, telling the men to put down their 9 mm handguns.

The men were carrying $10,098 in cash and deputies found a rental van they believe the fugitives planned to use in the escape, Martin County Sheriff's spokeswoman Jenelle Atlas said Tuesday night.

``They found the money on their person. We still don't know where it came from,'' Atlas said.

Investigators weren't saying where the van was parked or whether they had determined who rented it. Sheriff Robert Crowder said it is possible a third person was involved in the escape attempt.

Whitsett was convicted in 1994 of child molestation and finished his prison sentence in 1999. He was being held at the treatment center while awaiting a civil trial under a law aimed at keeping dangerous sexual offenders locked up after their jail terms.

Burkhart had been taking flight training for two months and was making only his second solo flight, according to the National Transportation Safety Board. He does not have an FAA license.

Florida Gov. Jeb Bush said Tuesday he wants an investigation into security at the treatment center.