OfficeMax ( OMX) said its chief financial officer stepped down amid an expanding internal probe into the company's accounting for vendor payments. Brian Anderson, who was named chief financial officer just after OfficeMax changed its name from Boise Cascade in November, will be replaced on an interim basis by Ted Crumley, a previous CFO. The company is searching for a permanent replacement. "We are disappointed that Brian is leaving after only two months of service," OfficeMax said. "We regret that his commitment to our business was not strong enough to allow him to make a long-term contribution." The office supply chain also said four employees have been fired in connection with the accounting probe, which was first disclosed in December. The company said Wednesday it is postponing the release of year-end financial results while the investigation, which is being run by the audit committee, continues. "To date, the company's investigation has confirmed the claims by a vendor to its retail business that certain employees fabricated supporting documentation for approximately $3.3 million in claims billed to the vendor by OfficeMax during 2003 and 2004," the company said. "As a result of information discovered in the course of its investigation, the company has expanded the scope of its investigation to include a review of the manner in which it recorded rebates and other payments from vendors for fiscal years 2003 and 2004," it said. "The issues involved in this aspect of the investigation principally involve the proper timing for the recognition of such payments." OfficeMax expects the investigation to end in the third week of February, and it doesn't expect the probe to delay the filing of its 10-K beyond SEC deadlines. The stock closed Tuesday at $30.30.