A witness in Scott Peterson's (search) murder trial presented evidence Monday that might support a motive — he was going broke and getting deeper into debt in the months before his wife was killed.

In 2002, Peterson was paying out nearly 70 percent of his average monthly take-home pay of $3,694 to cover credit cards bills and other fixed debt, not including everyday expenses, said Gary Nienhuis (search), an internal auditor for the city of Modesto.

"The payments ... were high in relation to the cash flow," Nienhuis told jurors.

A year earlier, Peterson's average income was higher — an average of $4,335 a month — and he was paying out 58.7 percent of it to make debt payments, said Nienhuis, who examined Peterson's tax returns, payroll records, credit card statements and other financial records.

Many financial experts say debt should not exceed 36 percent of a person's gross monthly income.

Prosecutors have suggested that in addition to being motivated by his affair with a massage therapist, Peterson hoped to gain from a $250,000 life insurance policy taken out on Laci Peterson more than a year before she vanished.

However, an expert who testified for the prosecution last week acknowledged that if no body was found, Peterson would not have been able to collect the benefits for seven years.

Prosecutors also sought to show Monday that Peterson's business, an American subsidiary of a foreign fertilizer company, was going broke.

"They weren't making money. It was not a profitable business," Nienhuis said.

Nienhuis said Peterson's company set for him a $422,000 sales goal for 2002, and as of November, he had made only 23 percent of that.

"Based on what you were seeing in the business was the defendant's job in jeopardy?" asked the prosecutor, Dave Harris. That prompted an objection from defense attorney Mark Geragos (search), and Harris moved on.

Geragos noted the parent company had about $500 million in sales in 2000 and was fully capable of withstanding any initial loss in setting up its American counterpart, Tradecorp.

Geragos then pointed out that Peterson's personal credit report showed "great" standing, and that all credit agencies indicated his payments were always received on time.

Geragos also noted that Laci Peterson (search) was set to inherit about $160,000 from her grandmother's estate, and another $100,000 worth of jewelry.

Nienhuis testified the couple's total debt, including their house mortgage, was about $210,000, but acknowledged that the inheritance would have greatly helped them.

The auditor also admitted he did not review anything beyond 2002. In addition, Nienhuis said he was unaware Peterson had sold his $23,000 membership to an area golf club — nearly the exact amount, Geragos noted, of Peterson's outstanding credit debt, not including his home and car payments.

Peterson, 31, could face the penalty or life without parole if convicted.

Prosecutors allege Peterson killed his wife in their Modesto home on or around Dec. 24, 2002, then drove to San Francisco Bay and dumped her weighted body from his small boat. The badly decomposed remains of Laci Peterson and the couple's fetus washed ashore in April 2003, not far from where Peterson said he went fishing the day she vanished.