It appears a southern governor kidnapped by presumed leftist rebels on his birthday had his throat slashed within a few hours of the abduction, a Colombian investigator said Wednesday.

The body of Caqueta state Gov. Luis Francisco Cuellar was found face down on a rural hillside Tuesday nine miles (15 kilometers) from his house in the state capital of Florencia, said the state's chief judicial investigator, Manuel Hernandez.

He had an 8-inch (20-centimeter) gash across the neck and there was no sign of a struggle, Hernandez said. Military officials speculated Cuellar's captors killed him because security forces were in pursuit but there was no sign of combat in the area, Hernandez told The Associated Press.

A rebel commando unit of eight to 10 men dragged Cuellar out of his home late Monday while he was still in his pajamas. It was Cuellar's 69th birthday.

Cuellar had previously been kidnapped four times since 1987, each time for about two to seven months and in each instance an undisclosed ransom was paid.

One of his sons, Luis Fernando Cuellar, speculated Wednesday that his father was killed because he refused to be herded into the mountains by his captors.

The son told the AP by telephone that his father had said he wouldn't submit to a fifth kidnapping. "He said, 'The day I get kidnapped again I won't walk a single step.'"

"I think he just refused to walk anymore," he said.

Monday's kidnapping, Colombia's first major political abduction since 2002, underlined the threat still posed by the Revolutionary Armed Forces of Colombia despite years of being battered by the Andean nation's U.S.-backed military.

The FARC didn't immediately take responsibility for the kidnapping, but it has a history of staging publicity-grabbing attacks during the Christmas holidays.

"In the midst of pain, we reiterate today all our determination to defeat these terrorists," Colombian President Alvaro Uribe said in a televised speech to the nation late Tuesday.

Uribe said senior military officials told him that "because security forces were in pursuit, the terrorists, so as to avoid gunfire, proceeded to cut the governor's throat."

Earlier Tuesday, an angry Uribe, whose rancher father was slain by leftist rebels in a 1983 botched kidnapping, said he had ordered soldiers and police to rescue Cuellar, who also was a cattle rancher.

Officials have offered a $500,000 reward for information leading to Cuellar's abductors. Colombia has effectively used millions in reward money to secure rebel defections and betrayals.