The would-be killers mounted a daring plan: renting a property adjacent to Colombian Defense Minister Juan Manuel Santos' suburban farm and secreting police uniforms, weapons and motorcycles at the site to facilitate a Holy Week assassination.

Once again, Colombia's largest rebel group, known as the FARC, was trying to kill Santos.

In revealing the foiled plot this week and announcing the arrests of 11 alleged rebel conspirators, Colombian National Police commander Gen. Oscar Naranjo said it was the 11th such scheme uncovered against the minister in less than two years.

Analysts say Santos is a target of the leftist Revolutionary Armed Forces of Colombia, or FARC, because he is a front-runner in the 2010 presidential race and if elected probably would continue President Alvaro Uribe's hard-line approach. Santos gets much of the credit for the Colombian armed forces' battlefield successes against the rebels since he became minister in July 2006.

Rebels have succeeded in getting close to Santos. In late 2007, police arrested FARC urban militia member Marilu Ramirez, who had befriended a Santos maid and inveigled a visit to the minister's house to advance an assassination plan, police say.

Other attempts involved car bombs and ambushes. Police say the most recent plot and most of the others were led by the FARC's special terrorist teams, the Teofilo Forero Column and the Antonio Nariño Urban Network.

The two groups have pulled off several brutal attacks over the years, including kidnapping 12 state lawmakers in Cali in 2002; the bombing of the Nogal social club in Bogota, which killed 36 in 2003; and the slayings of nine Rivera city council members in 2006.

Revenge could be another motive. Santos planned the attack that killed the FARC's No. 2 commander, Raul Reyes, in Ecuadorean territory in March 2008, an operation that sparked a regional crisis but which the minister continues to defend as appropriate.

Santos also directed the rescue of three U.S. defense contractors, former Colombian presidential candidate Ingrid Betancourt and 11 other hostages in July that had army commandos posing as human rights workers.

"Under Santos, the armed forces have struck major blows that have done huge political damage to the rebels, amid accelerating defections of FARC fighters, including important leaders," said Jaime Zuluaga, a political scientist. "So it's not surprising the rebels see him as a propitious and symbolic victim."

The latest scheme had rebels disguised as police forcing their way into Santos' family compound in Anapoima about 60 miles southwest of Bogota, the capital, and killing him. Rebels were also targeting Santos' brother, Enrique Santos Calderon, a top editor at El Tiempo newspaper and current Inter American Press Assn. president.

"The FARC is behaving like cornered beasts," the defense minister told a reporter Thursday. "They wanted this to be a Black March for Colombians as a response to the Black March they had last year, but they couldn't make it happen."

The plot came to light after the capture in October of FARC leader Jose Marbel Zamora, alias "El Chucho," and the recovery of his laptop computer. The operation against Santos was detailed in the computer's electronic files, and there were also descriptions of his family members and their movements.

At his capture, Zamora was commander of the Antonio Nariño urban militia group, which is charged with extorting money from businessmen and landowners in the Bogota area as well as procuring arms and supplies for fighters in the countryside.

The FARC received another blow last month when Zamora's successor, known as "Negro Antonio," was captured.

chris.kraul@latimes.com