(CBS) — It was Monday when 24-year-old Heriberto Godinez died in police custody – and this afternoon the lawyer for Godinez’s family says he thinks Chicago Police killed him.

The autopsy results: officially inconclusive, pending more testing.

Police have said that when Heriberto Godinez was arrested, he was having trouble breathing – and died later.

A law enforcement source tells WBBM that police believe Godinez had ingested something about the time of his arrest.

But the attorney for Heriberto Godinez’s family, Jeffrey Granich, says he’s heard a different story from people who were at the scene in Brighton Park early Monday.

“One witness described it as a very large police officer with his knee in the back of Heriberto’s neck, while Heriberto was face down on the ground.”

Granich says police have told the family nothing about the case.

“I believe that Heriberto died at the hands of the Chicago Police Department. And generally when an individual’s life is taken by another individual, that’s a homicide.”

Granich says a source at the medical examiner’s office told him that Godinez’s neck may have been broken.

The ME’s office has released a statement, promising to review witness accounts and to seek consultation to determine if there was disease or injury to the brain, neck or spinal cord.