BOGOTA, Colombia — The stunning rescue of Ingrid Betancourt and three U.S. military contractors owed its success not just to artful deception, but also to a five-year U.S.-Colombian operation that choked their captors' ability to communicate.

Known as "Alliance," it began with a satellite phone call in 2003, just weeks after the Americans' surveillance plane crashed in the southern Colombian jungle, according to U.S. and Colombian investigators and court documents.

The call came from Nancy Conde, the regional finance and supply chief for the Revolutionary Armed Forces of Colombia, or FARC, whose boyfriend would become the American hostages' jailer. She was calling confederates in Miami to see if they could supply the rebels with some satellite phones.

What Conde didn't know was that state security agents were listening.

U.S. law officers arrested the Miami contacts, who in exchange for promises of reduced sentences put Conde in touch with an FBI front company, according to a U.S. law enforcement official involved in the investigation, who spoke on condition of anonymity for security reasons.

Over more than four years, that company provided wiretapped satphones and other compromised telecommunications equipment that threw the rebels off balance and eventually helped authorities strangle their supply lines.

The operation laid crucial groundwork for the brazen July 2 commando rescue of 15 hostages held by a rebel unit that Conde supplied, the biggest blow ever dealt to the FARC.

In all, U.S. and Colombian agents intercepted more than 5,000 rebel phone conversations, investigators told The Associated Press.

They allegedly heard Conde and her coconspirators negotiate shipments of everything from assault rifles to condoms for distribution to about a third of the FARC's estimated 9,000 fighters, including the 1st Front that held the hostages.

"We're not talking just about finances, communications equipment, food and weapons — but also medical supplies, medicines and people who cared directly for the wounded," said Luis Ernesto Tamayo, the security official who ran the Colombian side of the operation. He wouldn't say whether hostages were discussed in any of the intercepted conversations.

Many of the calls went to a rebel "call center" in the gateway city of Villavicencio, where radio communications from the jungle were relayed to international phone circuits.

On Feb. 2, authorities pounced on Conde, arresting her as she entered Colombia from Venezuela, where she'd gone to give birth. They rounded up a total of 39 alleged members of her supply and communications network, including three doctors — one of them a 61-year-old Cuban — and two of Conde's three female deputies.

The arrests, which began in 2006, notably included the capture of Jose Maria Corredor at a jungle camp. He allegedly shipped in hundreds of assault rifles from Venezuela in exchange for cocaine.