Key witness takes stand in 2014 double-murder trial in Camden County

CAMDENTON, Mo. -- Jennifer Gerber was called as a witness by the prosecution to describe her marriage to Chad Gerber, her affair and relationship with Matthew Rumbaugh, and the details that led to Chad and his son Riley's 2014 deaths.

Gerber was given immunity in 2017 by the prosecutor's office after she had previously refused to testify during pre-trial hearings.

"She's the only person who was there from start to finish who saw everything that happened," said Mark Gerber, brother and uncle to the victims.

Jennifer Gerber told the jury today her marriage with Chad was good and bad, and she had often left him, but always went back.

At some point in their relationship, she started working for Rumbaugh, and the two had a secret affair.

He had purchased her a phone to call and text him from, but after not responding to him while she and Chad were going to a casino in Oklahoma, Gerber said Rumbaugh texted Chad and told him about the affair.

Gerber says she and her late husband had both had affairs during their marriage, but they decided to work through this.

Shortly after that trip, Gerber said she got home and Rumbaugh came out of the woods and asked why she hadn't left her husband. She said he showed a gun, an envelope of money, and said he would "put a mob hit" on her, Chad, and their daughters.

They got a restraining order against Rumbaugh.

Gerber says on July 7th, 2014, her family went to bed around 9:30. A few hours later, they woke up to a loud bang. She said Chad jumped up, shouted, and fell to the ground.

Gerber told the jury Riley came running in and they had struggled to keep the shooter - who Gerber identified as Rumbaugh, from their daughter's room. Riley was then shot in the head.

Gerber said Rumbaugh forced her into his car and drove off, telling the girls if they called 911 he'd kill their mother. But, she said he took her back to the home and she called police.

Despite testimony from Jennifer Gerber, her daughters, two separate interrogation videos of Rumbaugh, and ballistic evidence testimony, Chad Gerber's brother, Mark, feels the prosecution hasn't been as strong as his family had expected.

"I think everybody just needs to take a deep breath when we see these things happen, and then wait for the complete picture to be constructed," Mark Gerber said. "If after that we think it hasn't been done satisfactorily, I think a few of us will speak our minds."

Despite this, Mark Gerber says he's still as hopeful as he was before the trial started Friday that his family will see justice served.

"In lieu of everything that we've seen thus far, there would have to be something out of left field that would render this, something, a result that we're not expecting to see. "

The trial is scheduled to end on Friday, but the family says they think it might not end until Monday.

Read the original version of this article at www.ky3.com.