PROSSER-- A man and his two rescue therapy dogs died on their way back from helping at a nursing home when their pickup collided with a commercial truck in Richland Friday.

David Kelso and his dogs, Casper, a four-year-old Japanese Akita, and a three-year-old German Shepard named Lakota, were well known at Prosser Memorial Hospital, where Kelso worked as a surgery department manager.

"He was a very effervescent sort of guy," said Prosser Memorial CEO Jim Tavary. "Very authentic, very genuine, really quite compassionate about health care, a consummate professional. Really fun to be around.

Kelso had a Ph.D and a nursing degree, and Tavary said he improved Memorial's surgery department exponentially since he arrived from New Mexico less than a year ago.

But Kelso was best known for his community service with his remarkable dogs. Casper had recovered bodies in search and rescue operations, and both dogs were trained to help disabled people and provide psychotherapy.

"They were just incredibly intelligent dogs," said Lou Hamilton, who took care of them at her Doggy Daycare while Kelso was working at the hospital. "He had a Ph.D. I consider his dogs had Ph.D's because they were the most educated dogs I ever met."

Hamilton said Casper brought smiles to the faces of unresponsive patients. Kelso took the dogs to Prosser Memorial Nursing Home every Friday to work and play with the residents there.

"Just the understanding that it's Friday and Dave's coming with his dogs, made getting up in the morning a lot more exciting for his nursing home residents," said Tavary.

The three of them were on their way back from one of those therapy sessions Friday, when Kelso's pickup collided with a commercial truck in Richland.

"When I heard that the was dead, that was incomprehensible to me, because he was just here yesterday afternoon, so excited, playing with his dogs, going for the therapy," said Hamilton. "He was just so thrilled that he could help people with his dogs, and Dave loved people."

State Troopers are still investigating the cause of the accident. They are not ruling out alcohol, and are looking into whether Kelso's diabetes played a role.

The driver of the commercial truck was not hurt in the accident, according to Richland police.