Chicago, Illinois (CNN) -- A body found Monday in the Chicago River is that of Michael Scott, president of the Chicago Board of Education, police said.
A medical examiner has ruled Scott's death a suicide, Police Superintendent Jody Weis said, but authorities have not completed their investigation. There was a gunshot wound to the head, police said.
Scott's family had reported him missing about midnight, and his body was found about 3:20 a.m., Weis said. He was last seen about 6:30 p.m. Sunday, Weis said, but he would not disclose where, saying that may be part of the investigation.
Scott's wife told police that it was "very unusual" for him not to be home by midnight, Weis said.
The gunshot entrance wound was on the left side of his head, police said. A weapon was found either under or alongside his body, Weis said, and Scott's car was in the immediate area.
The police investigation will include ballistics evidence and analysis of surveillance cameras in the area, Weis said. It is too early for police to draw conclusions, he added.
"Mr. Scott was a strong advocate for education," Cook County Board President Todd Stroger said in a written statement. "His contributions to the minority communities of Cook County will be sorely missed, in particular, his love for the upward mobility of residents from Chicago's West Side, where he spent his life."
In Washington, U.S. Education Secretary Arne Duncan also mourned Scott's death, saying he was "shocked and saddened by the sudden death" of his "friend and colleague.
"Michael cared passionately about public education and made many courageous decisions as president of the board. He gave his time, energy and talents to improving the life chances of children.
"Chicago has lost a great leader, and the city's school children have lost a devoted champion."
Duncan was the chief executive officer of the Chicago school system from 2001 to 2008.
The Rev. Jesse Jackson recalled first meeting Scott about 30 years ago.
"We're just stunned and shocked," he said. "Michael was so effervescent, so full of life."
Scott had been appointed to the Chicago Board of Education three times, twice as president. He most recently was appointed in February. Previously, Scott was board president for five years, until July 2006.
Scott disclosed in early August that he had been subpoenaed to testify before a federal grand jury investigating how students were chosen for admission to some of Chicago's most elite public schools.
He denied using his influence during two stints as board president to help any student into a selective-enrollment school.
Scott, who was a developer, also was criticized in August when it was revealed that he had quietly arranged to develop city-owned land near a park that would have been used in the 2016 Summer Games. The move would have positioned Scott to cash in, had Chicago been awarded the Olympics.
The 2016 Games were awarded to Rio de Janeiro, Brazil.
CNN's Mark Bixler contributed to this report.