HOUSTON -- A federal judge on Tuesday dismissed one of seven counts against Enron founder Kenneth Lay and three of the 31 counts against former Enron CEO Jeffrey Skilling.

U.S. District Judge Sim Lake's decision came after federal prosecutors rested their case in the fraud and conspiracy trial of Lay and Skilling.

According to Skilling's defense team, Lake dropped two counts of securities fraud and one count of wire fraud against Skilling, leaving him with 28 criminal counts against him. Lake also dropped one securities fraud count against Lay.

The defense is scheduled to open its case on Monday, which is expected to feature testimony from both defendants.

Defense lawyers have pared down their witness list to about 100 from more than twice that. One-fourth or more of them are likely to testify.

The two are on trial on federal fraud and conspiracy charges relating to Enron's 2001 collapse into bankruptcy.

The government presented 22 witnesses since testimony began Feb. 1.

The list of witnesses included eight former executives who have pleaded guilty to crimes. One had an immunity deal. One had settled regulatory allegations, and three said they voiced concerns about financial peril that fell on deaf ears.

Lay and Skilling have denied any wrongdoing.

Skilling faces 28 counts of fraud, conspiracy, insider trading and lying to auditors for allegedly lying about Enron's financial strength.

Lay faces six counts of fraud and conspiracy for perpetuating the alleged scheme after Skilling resigned in August 2001.

If convicted, each could face decades in prison and millions of dollars in penalties.