IOWA CITY -- Police say Steven Sueppel killed his wife and four children late Sunday night or early Monday morning, and that they died of multiple blunt force trauma injuries to their torsos and heads.

Sueppel also left a series of voice messages and a written note apologizing for the murders. Sueppel was facing embezzlement charges, and he was recently fired from his job.

In the note and voice messages he left behind, he apologized for stressing out his family over the past few months.

He also said he was sorry for killing them. Police say Steven Sueppel killed his wife Sheryl first and left her body in the master bedroom. Then, he tried to kill himself and his four children using exhaust fumes in the garage. Apparently, it didn't work.

So, police say Sueppel killed each of the four children using some sort of blunt force.

He left the children's bodies in bedrooms throughout the home and put one child in the basement's toy room. Police found two baseball bats in the home that may be murder weapons.

"Most people we spoke to described it as an ideal family. Obviously, they had their problems here recently, but he was described as a kind, loving father and he and his wife got along well," Jim Steffen, an Iowa City Police Investigator, said.

After the murders, Sueppel tried to drown himself in the Iowa River near Lower City Park in Iowa City. When that didn't work, he headed out to the interstate and tried to kill himself again.

"The vehicle passed cars and trucks at a high rate of speed and appeared to travel directly into a concrete base that holds a highway sign," Iowa City Police Chief Sam Hargadine said.

Autopsy results show Sueppel died of blunt force trauma in the crash. The notes and voice messages he left didn't fully explain what caused him to snap, so we may never know the motive for the murders.

"I believe there are probably a number of theories about why this happened, but Steve is probably the only one who knew why he did what he did. I don't know that we're ever going to be able to determine the real reason why this happened," Steffen said.

Dealing with all the murders is hard enough, but not knowing why makes a devastating situation even harder for everyone who knew the Sueppel family.

Police are still waiting for autopsy results before they release the exact cause of death. In several of the voice messages Sueppel left for family and friends, he said that he believed his family was now in heaven.