The Paris prosecutors’ office said toxicology tests conducted as part of a post-mortem found traces of cocaine and cannabis in the blood of the suspect, Ziyed Ben Belgacem.
He also had 0.93 grams of alcohol per litre of blood when he died on Saturday, the prosecutors’ office said. That is nearly twice the legal limit for driving in France.
The 39-year-old Frenchman with a long criminal record of drugs and robbery offences stopped at a bar in the early hours of Saturday morning, around four hours before he first fired bird shot at traffic police.
Then, 90 minutes later, he attacked the military patrol at Paris’ Orly Airport, causing panic and the shutdown of the French capital’s second-biggest airport.
Yelling that he wanted to kill and die for Allah, Belgacem wrestled away a soldier’s assault rifle but was shot dead by two other soldiers before he could fire the military-grade weapon in Orly’s busy South Terminal.
In an interview with French radio Europe 1, a man identified as the suspect’s father said Belgacem was not a practising Muslim and drank alcohol.
He said: “My son was never a terrorist. He never attended prayer. He drank. But under the effects of alcohol and cannabis, this is where one ends up.”
Europe 1 did not give the name of the father, who was released from police custody overnight on Saturday. Belgacem’s brother and a cousin were released later on Sunday.
Belgacem called his father and brother early on Saturday morning, minutes after he fired at a police traffic patrol, injuring an officer in the face, to say that he had made a stupid mistake, according to Paris prosecutor Francois Molins.
The man identified as Belgacem’s father said on Europe 1: “He called me at seven, eight in the morning and said: ‘There you go, Papa.’
“He was extremely angry, even his mother couldn’t understand him. He told me: ‘I ask for your forgiveness. I’ve screwed up with a gendarme.’”
A subsequent police search of Belgacem’s flat found cocaine, Mr Molins said.
Belgacem had been flagged as having been radicalised during a spell in detention in 2011-2012, the prosecutor said.
His house was among dozens searched in November 2015 in the immediate aftermath of suicide bomb-and-gun attacks that killed 130 people in Paris.
The Orly attack forced both of the airport’s terminals to shut down and evacuate, sent passengers and workers fleeing in panic and trapped hundreds of others aboard planes that had just landed.
Mr Molins said that according to the soldiers, the attacker yelled: “Put down your weapons! Put your hands on your head! I am here to die for Allah. Whatever happens, there will be deaths.”
The drama, which caused no injuries except for the light wound to the traffic police officer, further shocked France, which remains under a state of emergency after attacks in the past two years that have killed 235 people.