Mumbai, Oct. 4: The mystery of two conflicting test reports on whether Indrani Mukerjea suffered a drug overdose deepened today but hospital authorities said she was "out of danger and off ventilator".

A forensic laboratory has said it has analysed samples from the blood, urine and gastric contents of the former television executive, who fell unconscious in jail on Friday, but found no evidence of a drug overdose.

But the JJ Hospital, where Indrani is recovering, says that pathology tests by the Hinduja Hospital, to which Indrani's blood and urine samples had been sent, indeed detected a benzodiazepine overdose.

Benzodiazepines are a group of drugs used to treat depression, anxiety and epilepsy. Jail sources have confirmed that Indrani, accused of killing daughter Sheena Bora in 2012, was being treated by a psychiatrist for depression in prison.

"Urine, blood samples and stomach wash were all negative. There is no trace of drugs. Possible drug overdose is ruled out," the forensic lab's deputy director, Nitin Chutke, told The Telegraph today.

If a drug overdose - with suggestions of a possible suicide attempt - is established, it would amount to a grave lapse on the part of jail authorities and reflect poorly on the state government.

T.P. Lahane, dean of the JJ Hospital, had yesterday said that only the gastric contents, and not blood or urine, had been sent to the laboratory and that these samples may have been collected too late to test positive.

Today, too, he insisted that the urine and blood tests at Hinduja had detected an overdose but added that he was "not rejecting" the forensic report, which has been sent to the state home department.

"The forensic test is authentic and reliable and we have accepted the findings of the report," he said, but added a rider.

"I must also say that we have treated Indrani for drug overdose, as revealed by the clinical findings and the Hinduja Hospital pathology reports. She has responded to this treatment and is now recovering."

A senior physician who is an authority on drug poisoning but was not involved in Indrani's treatment said, on the condition of anonymity, that what he had learnt through the medical grapevine indeed suggested a benzodiazepine overdose.

A PTI report has quoted Lahane as saying: "Normally if a patient is on an antidepressant drug, the level of benzodiazepine in the urine is 200 (units). But the level of benzodiazepine is 2,088 (units) as per the Hinduja report. The report is positive for drug overdose."

The expert who spoke to this newspaper concurred with Lahane's conclusion, saying he had learnt that Indrani had been prescribed the anti-depressants etizolam - a benzodiazepine - and mirtazapine.

He added that he had heard Indrani was given a kidney dialysis in hospital and antidotes for a benzodiazepine overdose.

The expert explained that evidence of such an overdose might not show in a forensic test on the gastric contents if the sample was collected more than three hours after the ingestion of the drug.

A hospital sources said the sample sent to the forensic lab had been collected eight hours after any possible overdose.

Lahane said Indrani was "a bit groggy still but fully conscious and on the road to recovery" and "should be discharged in two-three days".

On Monday, she will be questioned by the inspector-general (prisons) and Maharashtra home department officials, who are separately probing what led to her emergency hospitalisation.

A PTI report quoted the principal home secretary (prisons), Vijay Satbir Singh, as saying the probe would look into the overdose angle, covering all possibilities from negligence to foul play, and pin responsibility.