(CNN) -- A handwriting expert testifying for the defense said Wednesday that former Kansas police officer Brett Seacat did not forge a suicide note for his wife, Vashti, whose body was found inside the couple's burning home in 2011.
But in a possible blow to the defense, Avis Odenbaugh conceded in cross-examination that she is not currently certified by any forensic document examination organizations.
Brett Seacat is on trial for first-degree murder in Vashti Seacat's death.
Prosecutors say Seacat shot his wife and set fire to their home. The defense says it was Vashti Seacat who pulled the trigger after starting the fire.
Brett Seacat told investigators that his wife was depressed.
The alleged suicide note asks Brett Seacat to take care of their two boys: "Hold them both and tell them 'mommy loves them' every night."
It ends with a message to the children, telling them, "I love the two of you and will be watching over you from Heaven."
A prosecution expert earlier had testified that the note had not been written by Vashti Seacat.
But Odenbaugh testified she concluded that the handwriting in the note matched the handwriting of the person who wrote in Vashti Seacat's journals.
The prosecution was able to score a point during cross-examination, however, by getting Odenbaugh to admit she is not currently certified and is semi-retired.
Prosecutors also displayed a board with another sample of Vashti Seacat's writing alongside the suicide note. The expert admitted there are discrepancies between the two.
Jurors got to take a closer look at the two samples on handouts provided by the prosecution. CNN's Ted Rowlands said they seemed to be nodding in agreement that the samples had differences.
One of Brett Seacat's co-workers testified earlier in the trial that Seacat had asked for an overhead projector the day before his wife's death. The prosecution suggested in opening statements that Seacat used the projector to forge the suicide note.
Seacat has said he was sleeping downstairs on the night of the fire, CNN affiliate KWCH reported. He heard a noise, and moments later his wife called him on his cell phone, saying he should get their two boys before they got hurt.
He then purportedly heard two pops. Brett Seacat went upstairs and saw flames.
He reportedly said he found his wife in their bedroom and tried to save her.
But prosecutors say Brett Seacat's story doesn't makes sense.
For one, he had no soot or blood on him, they say, according to KWCH, and only a small burn on his foot.
He and the couple's sons escaped from the blaze unharmed.
The Seacats' home in Kingman, Kansas, sits not far from the courthouse where Brett Seacat is standing trial.
Despite extensive fire damage, the house still stands; a brick chimney pokes out of the charred remains.
"I'm smart enough that if I wanted to kill my wife ... I could've come up with something better than this," Seacat told investigators about the shooting and the fire.
"This is what a crazy person does."