Cause of Death of Daniel Smith Remains a Mystery

As I mentioned the other day, the combination of Lexapro and Ambien were not likely to have caused Daniel Smith’s death. If it’s true that Daniel was admitted previously for a fast heart rate, then it’s possible he could have died from Sudden Cardiac Death, which is caused by certain lethal electrical malfunctions of the heart muscle called lethal arrhythmias. The remaining test results are still pending, but here’s what experts know so far:

The initial toxicology report performed on Daniel Smith in the Bahamas shows only “therapeutic levels” of the antidepressant Lexapro, PEOPLE has learned.

The dosage is “nowhere near a toxic range” Cyril Wecht, the pathologist hired by Anna Nicole Smith to perform a second autopsy on her son, tells PEOPLE exclusively.

Still, Wecht said he has not yet ruled out an accidental fatal overdose of drugs because more tests have to be done. The initial findings are from the first toxicology tests performed by the coroner in the Bahamas, not from Wecht’s own tests, the results of which are expected next week.

Additional tests are also being conducted to check for the sleeping pill Ambien, Wecht told PEOPLE in a telephone interview Thursday.

According to Wecht, Smith’s Los Angeles-based doctor had given him a sample of Ambien but it’s not clear if Smith took the drug. Further tests need to be done to determine if Ambien was in Smith’s system.

“There’s no reason to believe there’s going to be a significant level of Ambien in him,” said Wecht. “It is not a powerful drug. You’d have to take a lot of it. It’s not the best drug if you want to drive but putting you to sleep is one thing – killing you is another.”

Wecht is also waiting on the results of tests on tissue samples from Smith, who died in his mother’s hospital room Sept. 10 while visiting her three days after she gave birth to a baby girl.

“Everything was ruled out in the major category of drugs,” Wecht said of the tests that have already been done. “They tested for tranquilizers, barbiturates, opiates. It would cover almost all the anti-depression, anti-anxiety drugs.”