The Alameda County Sheriff's Office received a call at 10:30 a.m. from someone reporting a body in a car on Via Alamitos, sheriff's spokesman J.D. Nelson said.
Deputies responded and found the body of James Izumizaki, 28, a teacher at Albany Middle School.
Izumizaki was arrested Wednesday after police began investigating a report that he had an inappropriate relationship with a former student at the school.
Nelson said that, based on the nature of the death and a note that was left, it appears Izumizaki took his own life.
Izumizaki was booked into the Santa Rita Jail after his arrest but had been released on bail. He had been a teacher at Albany Middle School for several years.
Albany Unified School District Superintendent Marla Stephenson said Izumizaki was heavily involved in student activities and had coached basketball and volleyball at the school.
Stephenson said she learned of the alleged misconduct last Monday, and that the school district contacted Child Protective Services and Albany police.
Izumizaki was placed on leave that afternoon.
It wasn't long before most everyone in Albany had heard news of the middle school teacher's death.
"I just found out about six o'clock. My wife told me. She heard it from somebody in the neighborhood," said Albany resident Bernard Knapp.
At Albany Middle School, students knew the popular 6th grade teacher as Mr. I.
"My parents got divorced in 6th grade and from that point on he was like my big brother. He was the biggest influence of my life and he still is," said Ben Chinen, a former student.
Police say they had not charged Izumizaki because they were still investigating. We asked why he was arrested before the completion of the investigation, but our calls to the Albany Police Department and the Alameda County District Attorney went unanswered.
Izumizaki graduated from Albany Middle School and Albany High School. He was scheduled to appear in court on Oct. 24.
Stephenson plans to hold a news conference about the case on Tuesday.
ABC7 News reporter Alan Wang contributed to this report.