NEW YORK (AP) — Prosecutors said they have recovered more than 70 percent of some $5.7 million a computer expert is accused of stealing from Columbia University by manipulating its bill-paying system.

The Manhattan District Attorney’s office expanded Wednesday on its case against George Castro. He was initially accused of stealing more than $4.4 million.

The 48-year-old Castro has pleaded not guilty to charges including grand larceny. His lawyer has said Castro expects to be vindicated.

Prosecutors said Castro had no formal relationship with the Ivy League university. They say he exploited a vulnerability in its payment system to channel money into his accounts.

Columbia declined to comment.

Prosecutors said Castro was arrested last month carrying $200,000 in cash and getting into a new $80,000 car.

(Copyright 2010 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)

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