The state wants to prevent testimony that a Kailua man was high on cocaine when he was shot to death by a State Department special agent.

Christopher Deedy, 30, is standing trial in state court a second time because the first one last year ended with the jurors deadlocked. He testified that he shot Kollin Elderts, 23, in the chest in a Waikiki McDonald’s restaurant on Nov. 5, 2011, in self-defense.

Deedy was in Honolulu to provide security for the Asia-Pacific Economic Cooperation summit.

Jonathan Arden, a forensic pathologist, testified in the first trial and in a pretrial hearing Wednesday that he believes Elderts was under the influence of cocaine and alcohol, based on the results of toxicology tests performed for the Honolulu medical examiner.

Those tests show that Elderts had a blood-alcohol concentration of 0.12. The legal threshold for drunken driving is 0.08.

The tests also show that Elderts’ blood contained benzoylecgonine, a substance the human body produces when it processes cocaine.

"That, of course, is a clear-cut indication that there was cocaine in the blood and therefore that the person is under the influence of cocaine," Arden said Wednesday.

The tests do not reveal the presence of cocaine in Elderts’ blood.

Arden said that is because cocaine breaks down quickly in blood, even after a person has died, and that the testing was done after the drug had enough time to clear.

The tests also show that there was cocaethylene, a substance the body produces when it processes cocaine and alcohol at the same time, in the thick fluid of Elderts’ eyeballs.

Clifford Nelson, a forensic pathologist who testified Wednesday on behalf of the state, said there is no evidence to support Arden’s opinion.

"Only the presence of cocaine in the blood or cerebral spinal fluid would establish (that) conclusion, and Mr. Elderts had neither," he said.

He said the fluid from Elderts’ brain and spinal column was not tested, and is rarely tested because the result will be the same as a test of the blood.

Both experts said benzoylecgonine does not affect the human body in the same way as cocaine but that cocaethylene does, though not to the same degree.

Nelson describes the concentration of cocaethylene found, 0.008 milligrams per liter, as "trace," saying it would have gotten into the eyeball fluid long after its effect on Elderts had worn off.

Deputy Prosecutor Janice Futa urged Circuit Judge Karen Ahn not to allow Arden to testify on whether Elderts was high on cocaine because his opinion is not reliable.

Deedy’s lawyer, Thomas Otake, told Ahn that she was right to allow Arden’s testimony in the first trial and should allow it in the second.

Ahn said, "The court ruled based purely on Dr. Arden’s initial letter. And then he testified, and he testified somewhat differently (from) some parts of his letter, not all. And the state challenged him."

She told the two sides she will inform them of her ruling by Monday. The trial could start July 10 with opening statements.