Sgt. Joyce Kemp said Maxime Trepanier, 27, was on the ground holding the cable when the accident happened early Sunday.
"When the hot-air balloon began to lift, he did not let go of it (the cable)," Kemp said in a telephone interview Monday.
She said she didn't have an estimate of how high Trepanier was carried into the air before he fell.
"There's still people who have to be met with — the family members and other witnesses — so that's going to be done throughout the week with investigators," Kemp said.
The experienced Trepanier was taking part in the 30th edition of a popular balloon festival in St-Jean-sur-Richelieu.
Transportation Safety Board spokesman Chris Krepski said Trepanier was helping the balloon land in nearby Mont-St-Gregoire when the accident happened.
"The accident took place while repositioning the balloon in a manoeuvre that consisted of ascending over a line of trees in order to land in an adjacent grassy field," Krepski said in a telephone interview.
"Winds were considered light at ground level but stronger at altitude."
Kemp said there is nothing to suggest any criminal wrongdoing or any negligence in the incident.
Quebec's workers' health and safety board is also investigating.
Trepanier was known as an experienced balloon pilot who had been involved in the balloon festival since his childhood.
In a statement, the festival offered its sympathies to Trepanier's family, which includes his wife and two young sons as well as his parents and two brothers.
"Son of a hot-air balloon pilot, Maxime Trepanier had been brought up in the world of ballooning," the statement said. "Having evolved in various levels of the sport in the last years, he was pilot of one of the eight balloons of the International Balloon Festival's fleet."
While shaken by the accident, festival organizers decided to continue with events through the week. It began Saturday and continues until Aug. 18.
The hot-air balloons were grounded on Sunday but paid tribute to Trepanier by simultaneously lighting up their burners, which provide the heat to lift the balloons aloft.
The Quebec firefighters academy, where Trepanier trained for his career, also observed a moment of silence on Monday.
"The academy family is in mourning today," said a statement on the institution's Facebook page. "We will remember his generosity, his smile and his love of life."
The International Balloon Festival of St-Jean-sur-Richelieu bills itself on its website as "the biggest gathering of balloons in Canada" and says it attracts 450,000 visitors a year.