The case of the 13th juror

Jurors deliberated for almost an hour and came back with a verdict. The trouble was there were 13 people who reached a decision, not 12.

It was the murder trial of a man accused of killing his girlfriend in the fall of 2007 in northwest Houston. Charles Mapps, 34, said he and his girlfriend, Roseann Siddell, planned a murder-suicide, but he stopped after killing her, then turned himself in.

"It doesn't take a long time for the state to put the case on. There really isn't any other evidence other than his statements," said Defense Attorney Skip Cornelius.

The case seemed to move smoothly through Judge Mark Ellis' court room where jurors were deliberating by the end of the third day.

As those deliberations began, the judge dismissed the alternate juror but court records show that's where the mishap began.

The alternate juror somehow ended up in the jury room and just as the verdict was about to be read they realized there were 13 jurors standing in the box.

That's when Judge Ellis declared a mistrial.

"I'm more concerned about the cost to the family of the victim," said Harris County District Attorney Pat Lykos.

Lykos said state code specifies that alternate jurors are not allowed into deliberations.

"If our prosecutors knew that there were thirteen people back there they would have informed the court because they are officers of the court," said Lykos.

The DA's office was minutes from a win but the guilty verdict by thirteen jurors was never was read on Tuesday.

"I'm not into the blame game but I think everyone should learn from this," said Lykos.

Cornelius was equally upset.

"It's just gonna have to be retried," he said. "We all basically lost today."

Cornelius was a prosecutor for ten years and says in his 38 years in the courtroom, this was a first.

"Some things happened that shouldn't have happened and this was the result. The judge was pretty upset about it," said Cornelius.

So the family of Roseann Siddell will have to relive the details of their daughter's death yet again.

"Somebody's gotta look and make sure this doesn't happen again, to insure that other families don't have to go through what this family has to go through with. It's just pure maddening," said Andy Kahan of the Mayor's Crime Victim's Office.

A new trial date has already been scheduled for Charles Mapps. He will go back to court in May.