A mother and her four children found dead in their Iowa City home were beaten to death, apparently by the father, authorities said Wednesday after autopsy results were released.

Sheryl Sueppel, 42, and the children died of injuries to their upper torsos and heads, Iowa City police said. Two baseball bats found in the home appear to have been used, police said.

Police believe the woman's husband, former bank executive Steven Sueppel, killed her and the children Sunday night or Monday. He had been charged with embezzlement, and his body was found in the wreckage of a car crash Monday.

Investigators say they believe he killed his wife, then tried to kill himself and the children by asphyxiating them with carbon monoxide in the garage. When that failed, he killed the children one by one.

Before he died, Steven Sueppel left a hand-written four-page note in which he detailed the killings. The note was left in the kitchen and apparently was written for surviving family members.

The note, clearly completed after he had killed the entire family, includes details that match evidence found at the scene and the medical examiner's findings, Kelsay said.

"It becomes kind of a moot point whether it was actually a ball bat or some other item," Sgt. Troy Kelsay said. "We're confident we know what happened, and we're not going to talk any more specifics."

The note also reveals some detail about Sueppel's frame of mind and what may have driven the former Hills Bank & Trust vice president and controller to the killings.

Sueppel mentioned in the note the embarrassment and other fallout from criminal charges he faced. A federal grand jury indicted him in February on charges that he stole nearly $560,000 between 2000 and 2007 from the bank.

Although he had pleaded not guilty, court documents indicate Sueppel had told investigators that he had taken hundreds of thousands of dollars and placed it in an account he held at another bank.

Sueppel was free on bond and awaiting trial next month.

In his note, Steve Sueppel discussed his life and the criminal charges, noting that his expected absence from home would leave his wife alone to raise and support Ethan, 10; Seth, 8; Mira, 5; and Eleanor, 3.

The U.S. attorney's office will request that the case against Sueppel be dismissed after it receives a copy of his death certificate, a spokesman said.