Khan said at the rate the body digests alcohol, Mostrong, now 21, could have had a blood-alcohol level of .07 or .08 and a few hours later the blood would show no signs of alcohol.
Deputy District Attorney Wayne Robinson, who has contended Mostrong was high on marijuana and had been drinking beer the night of Oct. 7, gave Khan a hypothetical situation.
Robinson asked Khan if an individual started drinking beer at 10:30 p.m. and continued to drink five 12-ounce cups filled with 10 ounces of beer and that person had an empty stomach and was of a certain height and weight, what would the person's blood-alcohol level be?
Khan answered it would be .07 to .08.
Robinson asked Khan to assume a person turned himself in 17 hours later, what would his blood-alcohol level be?
"Zero," Khan responded.
Khan said at the .08 level everyone is considered impaired by alcohol.
Robinson, in setting up his hypothetical situation, depended on testimony from California Highway Patrol Officer Pablo Torrez, who said he was told by witnesses they had seen Mostrong drinking beer at a "keg" party in the Superstition Mountains on Oct. 7.
Most witnesses have testified they could not recall whether Mostrong was drinking at the party. Some said it was possible he was, but they could not recall.
Only one witness testified he saw Mostrong drinking, and that he was drinking from a "beer bong."
As defense attorney Robert Espinosa of El Centro started his cross-examination of Khan, he took a drink from a white cup.
He asked Khan, "What did I drink?"
Khan responded, "I don't know."
Espinosa asked Khan if he knew how much he drank from the cup. Khan responded that he didn't know.
Espinosa then said when Khan said a person could have a .07 blood-alcohol level under Robinson's hypothetical situation, Khan had assumed some things he was not asked to assume.
Espinosa told Khan he wanted to deal with the same scenario, but without making any assumptions.
Espinosa told Khan he was making an assumption the beer had an alcohol level of 4 percent when it could have had a lower alcohol level.
Espinosa said Khan was making an assumption of how quickly alcohol is absorbed into the blood.
"If I drank five beers and you tested me right then, what would it be?" Espinosa asked.
"I don't know," Khan responded.
Espinosa said more than likely it would be .00.
"That's correct," Khan said, adding after 15 minutes the blood starts to show signs of alcohol in the system.
Espinosa said, "Take away the absorption time and give me what the blood-alcohol is and I bet you can't."
Espinosa added, "You don't know when absorption takes place. … Eliminate it from your brain. What is the final result?"
"I don't know," Khan said.
"So then you could retract it was .07," Espinosa told Khan.
"That is correct," Khan said.
The issue of whether Mostrong was under the influence of alcohol wrapped up a day of testimony without getting into whether Mostrong was under the influence of marijuana.
That issue is expected to come up in testimony when the trial continues Friday.
Thursday's hearing also saw Espinosa accused by an individual in the courtroom of recording the proceedings.
Espinosa had a tape recorder with him, and when Superior Court Judge Matias Contreras asked Espinosa whether he was recording the trial, Espinosa refused to answer the question.
He did start to play the tape as proof he was not recording the trial.
Contreras ordered him to turn off the recording and to answer the question.
Espinosa continued to refuse.
"I refuse to answer under grounds of my integrity," Espinosa said, adding, "Whatever idiot gave you that message does not have any sense."
Contreras twice told Espinosa not to interrupt him as Contreras ordered the tape recorder be taken from Espinosa until he answered the question.
Espinosa told Contreras he was taking away Espinosa's ability of "effectively representing my client."
Contreras responded that Espinosa had brought the action on himself, adding, "If at any time you answer the question you can get it back."
Espinosa said at no time has he ever recorded proceedings, and Contreras said in making such a statement Espinosa was answering the question.
Testimony will continue at 9:30 a.m. Friday.
Staff Writer Darren Simon can be reached at 337-4082.