One of the first victims struck by the Dayton shooter during his 32-second rampage that left nine people dead was his younger sister, but whether he intentionally killed her remains unknown more than a week later, the Ohio city’s police chief said Tuesday.

Investigators have “radically different views” on whether Connor Betts targeted his 22-year-old sister, Megan, two hours after they arrived with a friend at a popular strip of nightclubs, Chief Richard Biehl said at a news conference.

Text messages show the 24-year-old gunman knew his sister and their friend were going to a taco stand minutes before he came down an alley and started shooting, Beihl said.

“There’s a real question whether he could see who was on the other side,” the police chief said, adding that its possible investigators may never come up with an answer.

“If we can’t seem to make that call conclusively — that we’re divided about how, whether that was intentional or not — I think it’s inconclusive,” Biehl said.

Authorities have interviewed witnesses, studied video and reviewed Betts’ phone while trying to come up with a motive and other factors that led to the mass shooting Aug 4. So far, there is no evidence he had any help the night of the shooting, Biehl said.

While they don’t know why Betts chose his location or what his motive was, investigators do know a lot about his mindset, including his obsession with and desire to commit a mass shooting, the police chief said.

A video of pieced-together surveillance from businesses showed Betts before the shooting with his sister and their friend, and again after he went to his car and changed into a black hoodie, put on body armor and retrieved an assault-style gun from the trunk.

The three had arrived together at the entertainment district and spent about an hour inside a bar before Betts left and went to another nightclub by himself, police said.

He then walked back to his car and spent about eight minutes changing and getting out his weapon, Biehl said.

Investigators think the friend who arrived with Betts didn’t know what he had planned or that he had weapons stashed in the trunk, Beihl said.

Betts was very familiar with the area and its night spots and had been there the night before, the police chief said. It’s clear he had a plan for the mass shooting, although why he chose that place at that time is still being investigated, the police chief said.

In all, he killed nine people and wounded at least 17 others in just over half a minute before officers who were patrolling the area fatally shot Betts, police said. Previously, police and hospital officials said at least 14 people suffered gunshots.

The coroner’s report will determine whether anyone besides the shooter was hit by police, Biehl said.

Authorities said that a friend, Ethan Kollie, bought armor and a 100-round magazine for Betts, authorities said. But there was no evidence he knew what Betts planned, they said.

The governor’s office said Wednesday that its attorneys weren’t aware of any law that “would have necessarily prohibited” the magazine.

Kollie will appear Wednesday in federal court. His attorney said he has been cooperating with investigators.

“He was as shocked and surprised as everyone else that Mr. Betts committed the massacre,” attorney Nick Gounaris said Monday.

Prosecutors accused Kollie of lying about not using marijuana on federal firearms forms in the purchase of a pistol that wasn’t used in the shooting.

Police have said there was nothing in Betts’ background to prevent him from buying the gun.

The weapon was purchased online from a dealer in Texas and shipped to another firearms dealer in the Dayton area, police said.

Ohio Republican Gov. Mike DeWine has proposed a package of gun control measures , including requiring background checks for nearly all gun sales in Ohio and allowing courts to restrict firearms access for people perceived as threats.