The woman accused plowing her car into a crowd at the Oklahoma State homecoming parade did so intentionally, the state’s district attorney said on Monday.

According to the Associated Press, 25-year-old Adacia Chambers skirted a barricade, ran a stoplight and barreled over a police motorcycle before she hit the spectators. Chambers is facing up to four life sentences if convicted for the deaths of four people, including a toddler, the prosecutor said.

“The evidence suggests this was an intentional act, not an accident,” Payne County District Attorney Laura Thomas said in a statement. Thomas added that Chambers displayed evidence of “a depraved mind and indifference to human life.”

Police are waiting on blood tests to determine whether she was impaired at the time of the crash. But Chambers’ family and her attorney say that she is mentally ill, adding that she had received inpatient mental health treatment in the past.

“As far as for her to purposefully go and do something, that would just not be possible. ... She would never do anything like that consciously,” Chambers’ boyfriend, Jesse Gaylord, said at a tearful press conference on Monday.