Iowa City police managed to put together the pieces and solved the puzzle of what seems to be the city’s worst mass killing.

The investigators said that all the elements in the “equation” led them to believe that Steven Sueppel was the one that killed his wife and four children before killing himself by deliberately crashing with his van on Interstate 80. the murders and the crash took place either late Sunday or early Monday.

The funeral services for the six members of the family will be held at 10 a.m. on Saturday at St. Mary's Catholic Church, police said in a statement.

According to the investigation report, Sueppel first killed his wife, then tried to tried to kill himself and his four children by asphyxiation with carbon monoxide in the family’s garage. His attempt failed, but he didn’t stop there. Suepepel allegedly took his kids inside the house, one by one, where he killed them with a baseball bat.

After killing his entire family, the former bank director, tried to drown himself in the Iowa River. After failing to do so, he called 911 and told dispatchers they should send a patrol at his home immediately. He didn’t say why and he didn’t say his name.

A few minutes later he crashed with the family van on I-80. Investigators said he left a note in which he said he was having problems dealing with the situation he was in. Sueppel apologized "several times" in the note and also sent e-mail messages for his father, another relative as well as his former bank.

According to court records, Sueppel was indicted on federal charges Feb. 12 for embezzlement and money laundering in connection with almost $560,000 missing from Hills Bank & Trust, the bank where he was working. The 42-year-old pleaded not guilty.

Sueppel had “a separate account at another bank that he would deposit stolen monies into” according to Johnson County Sheriff's Detective Doug Gwinn.