Four men were convicted on Tuesday on charges of stealing $5.7-million from Columbia University by tampering with its electronic bill-payment system, according to news reports. Only one of the four was a university employee. Prosecutors said that employee, Joseph Pineras, a clerk in the finance department, received $10,000 for enabling the scheme. Another finance-department employee, Moise Jean-Paul, is also a defendant in the case but was not on trial with the four convicted on Tuesday. He has pleaded not guilty. A Columbia spokesman declined to comment on the case.