Joshua David Lambert will almost certainly spend the rest of his life behind bars as a convicted double murderer.

A jury found Lambert guilty Thursday on all counts, which include two counts of first-degree murder, one count of kidnapping and several burglary and gun charges.

The jurors rejected Lambert’s defense that he suffers from paranoid schizophrenia and was legally insane when he stabbed his two 80-year-old grandfathers to death and bound his great-aunt with packing tape on Oct. 3, 2011.

Prosecutor Greg Banks argued Lambert committed the horrendous and senseless crimes in the midst of a methamphetamine-induced psychotic episode.

The jury returned the verdict Thursday afternoon, after deliberating for about six hours.

Banks said Lambert is virtually guaranteed to receive a life sentence, especially since jurors found that he committed a series of aggravating factors, which increase the sentence substantially. The minimum time the 32-year-old man faces under the standard sentencing range is 67.5 years.

Lambert’s sentencing hearing hasn’t been set, but will likely be in the next month.

On Oct. 3, 2011, Lambert went on a frenzied search for guns to save his teenage son from non-existent “agents” and ended up killing both of his grandfathers.

Lambert stabbed his paternal grandfather, George Lambert, to death, tied up his great aunt Kay Gage with packing tape, and stabbed to death his maternal grandfather, August Eugene “Sonny” Eisner. His grandfathers were both 80 years old and lived in separate residences on North Whidbey.

Lambert granted a series of jailhouse interviews to the Whidbey News Group prior to trial. He explained the complex delusions he claimed to have on the day of the murders, as well as the voices that continue to plague him.

Thursday, attorneys and citizens who watched the trial agreed it was a predictable ending to a very unpredictable trial.

Lambert wasn’t in the courtroom for the verdict, but appeared from the jail on a large-screen TV with a video connection. Judge Vickie Churchill removed him from the court because of his continued angry outbursts, which culminated in a courtroom fight with guards Tuesday.

Psychologist Brian Judd, an expert witness for the prosecution, testified this week that he believed Lambert was delusional on the day of the murders, but that it was caused by shooting up methamphetamine. He noted Lambert’s extensive drug history, the fact that he was caught with hypodermic needles and jailhouse conversations Lambert had with his mother.

Judd also said Lambert likely exaggerated and embellished the symptoms.

Pacher appealed to the juror’s sense of humanity in his closing arguments. He opened with, “We never talk anymore.”

Pacher highlighted evidence that Lambert has a mental illness, which included talking to himself in prison. His behavior was so odd that a guard tried to get him a mental health assessment.

Pacher argued that Lambert’s mental health problems were compounded by his stay at an abusive boot camp for boys in Samoa and more than four years in solitary confinement in prison.

“Josh Lambert definitely has something wrong in his head,” he said.

Pacher didn’t try to soften Lambert’s difficult personality, but argued that shouldn’t matter.

“Frankly Josh is not an easy guy to like,” he said. “He’s contentious, he’s argumentative, he blurts out things.”

Finally, Pacher emphasized the lack of evidence that Lambert was on meth on the day of the murders. He also questioned the prosecutor’s experts; they cited the fact that Lambert hadn’t previously reported his delusional symptoms to authorities and his recent insistence that he’s insane as evidence against a diagnosis of schizophrenia.

“If you’ve read Joseph Heller’s ‘Catch-22,’ you’ll appreciate this,” he said. “If you don’t tell us you’re mentally ill, you’re not mentally ill. If you tell us you’re mentally ill, you’re not mentally ill.”

Banks, on the other hand, explained during his closing arguments that it’s not the state’s burden to prove that Lambert was sane; it’s up to the defense to prove he was legally insane at the time of the murders.

One of the elements of the insanity defense is the question of whether Lambert understood right from wrong. Banks said it was clear he did from his actions that day. Lambert, for example, didn’t kill his great aunt, but tied her up, even though he claimed he was authorized to kill by a voice in his head.

“That was an example of mercy,” Banks said. “And if he showed mercy, he knew right from wrong.”