The gunman in last week’s massacre in Dayton, Ohio, shot 26 people in 32 seconds, police said.

With the help of extensive video surveillance, police offered an updated timeline of the gunman’s movements and actions in the hours before he killed nine people and wounded 17 others outside a bar in the city’s popular Oregon entertainment district on 4 August.

Dayton Police Department said the gunman went to the district on the night of 2 August and returned with his sister and a friend at 11pm the following night. “He was not unfamiliar with this territory,” Chief Richard S. Biehl said.

After visiting a bar with them, the gunman left after midnight, the officials said, walking past a police vehicle to go to his car.

They said he went there about 15 minutes before the shooting to retrieve an AR-15-style rifle, ammunition and body armour. He returned wearing a dark hoodie and carrying a backpack, which contained the weapon, they said.

Ohio shooting: Gunman kills nine after opening fire outside bar Show all 21 1 /21 Ohio shooting: Gunman kills nine after opening fire outside bar Ohio shooting: Gunman kills nine after opening fire outside bar Several officers (top left and right) firing at Connor Betts (bottom left), who they identified as the gunman, seconds after he began killing people outside a bar in Dayton, Ohio Dayton Police Department/EPA Ohio shooting: Gunman kills nine after opening fire outside bar Betts killed nine people including his sister, and injured 26 others. He was also shot dead at the scene by the responding officers Dayton Police Department/AP Ohio shooting: Gunman kills nine after opening fire outside bar The Anderson Manufacturing AM-15 rifle with a 100-round double drum magazine which Connor Betts used Dayton Police Department/EPA Ohio shooting: Gunman kills nine after opening fire outside bar Surveillance footage of people beginning to flee from the sound of gunshots fired by Connor Betts Dayton Police Department/EPA Ohio shooting: Gunman kills nine after opening fire outside bar Police officers move towards Connor Betts Dayton Police Department/EPA Ohio shooting: Gunman kills nine after opening fire outside bar The vehicle which Connor Betts traveled to the scene in Dayton Police Department/EPA Ohio shooting: Gunman kills nine after opening fire outside bar Bodies are removed from the scene of a mass shooting in Dayton AP Ohio shooting: Gunman kills nine after opening fire outside bar The city's mayor, Nan Whaley, said the shooter was wearing body armour and used a ".223 high-capacity" gun during the assault. “In less than one minute, Dayton first responders neutralized the shooter.” AP Ohio shooting: Gunman kills nine after opening fire outside bar The FBI is assisting with the investigation Derek Myers/AFP/Getty Ohio shooting: Gunman kills nine after opening fire outside bar It was the second mass shooting in the US in less than 24 hours AP Ohio shooting: Gunman kills nine after opening fire outside bar Witnesses comfort one another at the scene AP Ohio shooting: Gunman kills nine after opening fire outside bar Police tape drapes over a chair near a pile of shoes. The shooting took place in the popular bar and nightlife area, Oregon district Dayton Daily News via AP Ohio shooting: Gunman kills nine after opening fire outside bar Dayton police look for evidence Dayton Daily News via AP Ohio shooting: Gunman kills nine after opening fire outside bar Shoes piled outside the scene AP Ohio shooting: Gunman kills nine after opening fire outside bar Residents comfort each other as they await word on whether they know any of the victims AP Ohio shooting: Gunman kills nine after opening fire outside bar Authorities retrieve evidence markers AP Ohio shooting: Gunman kills nine after opening fire outside bar Evidence markers lay on the ground near a hotdog stand Reuters Ohio shooting: Gunman kills nine after opening fire outside bar Evidence markers rest on the ground after a mass shooting in Dayton, Ohio, U.S. August 4, 2019. REUTERS/Bryan Woolston BRYAN WOOLSTON Reuters Ohio shooting: Gunman kills nine after opening fire outside bar People fill the streets during a vigil EPA Ohio shooting: Gunman kills nine after opening fire outside bar Mourners gather to recognise the victims Getty Ohio shooting: Gunman kills nine after opening fire outside bar Mourners leave flowers and candles at the entrance of Ned Peppers bar Getty

He text his sister and another victim minutes before he started shooting.

The gunman’s sister was among the first people he shot. Though the gunman knew where she and her companion were, he said the department could not conclusively say whether she was a target.

“We have radically different views in this regard,” Mr Biehl said of the many officers who reviewed the video evidence. “Based on the evidence of that night, I don’t think we can make that call.”

The gunman started shooting at 1.05am, striking 26 people in less than a minute before he was fatally shot by an officer. The chief added that the gunman did not wear his body armour in the most protective manner.

“Their response was crucial,” Mr Biehl said of his officers. “Their response was immediate. Their response was effective. And their response was compassionate.”

Mr Biehl did not say whether any victims were struck by bullets fired by his officers, leaving that ruling to the coroner’s report.

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There was some evidence of drug paraphernalia in the gunman’s car and that he was awaiting toxicology reports to state whether there was evidence of drug use.

He said the gunman had “undergone some treatment” but would not elaborate.

The police said the gunman was obsessed with mass shootings but declined to say what motivated the attack.