What experts say about the sanity of the man who killed a Pasco school bus driver

Video footage from a Pasco school bus is the most compelling evidence that the man who killed the driver knew what he was doing and that it was wrong, a state psychologist testified this week.

Washington state forensic psychologist Richard Yocum testified that Joshua D. Davis’ behavior during and immediately after his a attack shows he was legally sane and should be tried for murder.

Davis is charged in the deadly stabbing of school bus driver Richard Lenhart in September 2021 outside of Longfellow Elementary School as Lenhart was about to drive away with a busload of students.

“From the moment (Davis) stepped onto the bus to the time when he’s in the back of the patrol car .... , it appeared to me to be very controlled and very organized and very well-directed,” Yocum testified in Franklin County Superior Court.

“The next critical thing to me would have been the statements made by some of the witnesses that he referred to himself as an assailant,” Yocum said.

Davis, now 38, previously pleaded innocent by reason of insanity to premeditated first-degree murder. No children were hurt.

Davis’ sanity hearing began in late October but needed to be delayed because of scheduling issues for the experts. and court officials.

Yocum and defense expert Alexander Patterson agree that Davis suffers from schizophrenia, but they differ on how much he was affected by the symptoms that day.

Patterson testified for about 5 1/2 hours over the two-day hearing.

He said he believes Davis suffered a lengthy and extreme period of mental illness that caused him severe pain and left him unable to understand right from wrong.

He said Davis documented his problems in a series of about 60 videos, which show him putting a needle in his face, wheezing, screaming and crying hysterically. In one, he shaves off a large chunk of his hair on his head. Davis believed he was being targeted by the U.S. government using a sonic weapon.

He said he believes Davis doesn’t remember what happened.

However, Yocum focused his analysis on the time immediately around the attack. He said each action showed Davis understood that he was killing Lenhart and that he knew it was wrong, including covertly slipping the knife out of his waistband before an attack.

He had asked for a ride and pulled out the knife when Lenhart said no.

Yocum was skeptical about Davis’ claims that he doesn’t remember much of the day of the attack.

If Judge Jackie Shea Brown finds Davis was not sane, he will be held at a Washington state psychiatric hospital until doctors feel he is safe to be released.

For much of the last three years, his criminal case has been on hold during the investigation and he underwent mental health evaluations.

Psychiatric evaluations

Yocum and Patterson said their evaluations were hindered by Davis not explaining what he was thinking at the time of the stabbing.

Yocum used the bus and body camera video, testimony from witnesses and police reports, as well as interviews he had with Davis, for his evaluation.

He said one of the most influential pieces of evidence was the video from the bus. It showed Davis walk up to the closed bus doors. When Lenhart opened them, Davis stepped inside and asked if the bus went to Road 100.

When Lenhart answered that it wouldn’t, Davis turned away. And when Lenhart turned back to focus on driving the bus, Davis’ hand moved to his waist to pull out a knife.

Davis then lunged at Lenhart and stabbed him several times. When Lenhart got his feet between himself and Davis, Davis pushed him away.

Davis hopped off the bus and tossed the knife on the ground. When a school employee asked if he was a bus assistant, Davis said he was the “assailant.”

Yocum said that was significant.

Davis also apologized to Pasco Officer Joshua Madsen for ruining the name Joshua.

Police later discovered a note Davis left for his roommate that started by saying, “If you are reading this, then I’ve murdered children.”

The note continued and gave her instructions on giving his kittens to his mother.

Defense Attorney Shelley Ajax questioned Yocum about whether someone who can’t tell right from wrong might use deception.

He explained that using deception is an indication that someone’s thought processes are not so disorganized that they aren’t thinking about the consequences of their actions.

Extremely psychotic

Patterson testified that he believes Davis was sincere in saying that he doesn’t remember what happened on the bus and that his schizophrenia was so severe at the time that he wasn’t able to store the memories about the attack.

“I found him incredibly sincere, very confused about what was going on with him mentally and physically, but I found him to be very sincere,” Patterson said.

Patterson said he doesn’t know why Davis turned away before taking the knife from his waistband.

“To me, it didn’t seem relevant because people can commit acts or do things using deception that they think are rightful to do,” Patterson said. “The video is not super clear to me exactly what the purpose is there.”

He said people might sneak up on someone who they feel put them in danger.

This story was originally published April 18, 2025 at 12:26 PM.