A member of a bungling team of jewel thieves pleaded guilty to his role in a $3.5 million Diamond District heist that the feds are calling an inside job.

Eduardo Cartagena-Delgado, 24, faces as much as 13-1/2 years in prison for conspiring to commit three jewel thefts.

Cartagena-Delgado told Manhattan Federal Court Judge Harold Baer that he was recruited in November 2005 to travel from his native Puerto Rico to New York so he could help stage a robbery of Doppelt & Greenwald at 580 Fifth Ave – reported HERE on YWN.

The feds say gunmen dressed as FedEx workers burst into the store flashing weapons and handcuffing employees before tossing millions of dollars worth of loose jewels into duffel bags.

Prosecutors say the mastermind of the heist was the store’s co-owner, Brian Greenwald who tried to recover an insurance payout for the staged heist.

Cartagena-Delgado was also part of the heist team that held up a FedEx driver at gunpoint in December 2007. The thieves were forced to abandon $1 million in jewels on a Brooklyn street because they couldn’t figure out how to disconnect six cargo containers from the floor of an 18-wheeler.

Cartagena-Delgado and the others were arrested in December as they were plotting another heist of a FedEx truck carrying jewels.

Prosecutors say the 38-year-old Greenwald was behind both FedEx plots. He is being held at the federal lockup in Brooklyn.