Sonus Networks Inc. (Nasdaq: SONS) says that faulty accounting and an independent audit are among the causes delaying its earnings report for the period ended December 31, 2003 (see Sonus Explains Delay in Q4 Results). The softswitch maker saw its shares fall $1.37 (20.45%) to $5.32 in after-hours trading Wednesday after explaining its delay.

The company has already fired a non-executive employee and hired Hale and Dorr LLP and PricewaterhouseCoopers to help audit its finances and investigate problems. Calls to Sonus weren't immediately returned on Wednesday evening.

The company says it has told the Securities and Exchange Commission (SEC) of the investigation and will keep the agency posted.

“We are deeply concerned and disappointed to have discovered that certain employees at Sonus Networks were engaged in behavior that violated our code of conduct and may have compromised the integrity of our financial reporting,” said Hassan Ahmed, the company's president and CEO in a prepared statement.

— Phil Harvey, News Editor, Light Reading