ROCHESTER, N.Y. (AP) — A fourth person has died nearly two weeks after a driver crashed an SUV packed with gas cans near a crowd of New Year’s concertgoers in western New York, but authorities said Friday they may never know the motive for what they call an intentional attack.

Rochester police revealed Friday that motorist Michael Avery, 35, spent several hours in parking lots and other spots near the Kodak Center on the night of the fiery wreck, which killed him, two passengers in another car and a pedestrian who died earlier this week. Avery even went up to the theater and bought a ticket to the show, but didn’t go in, Police Chief David Smith said at a news conference.

Along with gasoline-filled canisters, investigators found a replica gun and lighters in Avery’s rented Ford Expedition, Smith said. There was also a 20-page journal with sporadic entries that appeared to be several years old and unrelated to the crash, the chief said.

Rochester Mayor Malik Evans said that Avery mounted a planned “assault on innocent people” and that his actions made plain “that he wanted to do more.”

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“We may never know why he decided to carry out this act,” Evans said.

Investigators have searched Avery’s hotel room, storage unit, his own car — parked at Rochester’s airport — and more. Authorities are working their way through hundreds of hours of surveillance video and have interviewed people who knew him. Investigators haven’t found any co-conspirators, any ties to “extremist ideologies” or indeed any motive so far, Smith said.

He said Avery, a sometime delivery driver who lived in the Syracuse area, had had behavioral problems. But his family saw no immediate signs of trouble last month, Smith said.

Avery spent the last few days of December in the Rochester area, buying and filling multiple gas cans, police said.

Then, around 1 a.m. on Jan. 1, he drove the Ford Expedition into an oncoming traffic lane and appeared to be headed for a crosswalk filled with people leaving a show by the jam band moe.

The SUV hit a ride-hail vehicle, and both careened into the crosswalk. Two ride-hail passengers, friends Justina Hughes and Joshua Orr, were killed, and several other people were injured, many of them pedestrians.

One of the injured, Dawn Revette, 54, died Wednesday, Smith said. Revette lived in Rochester.

The police chief said one person is still hospitalized, with injuries that aren’t considered life-threatening.