A man is believed to have killed his wife and teenage son, before committing suicide in their southwest suburban Oak Forest home.

Oak Forest Police Chief Gregory Anderson said Tuesday that the family were having financial troubles after the father had lost his job.

Officers said they discovered the bodies of 54-year-old David Joost; his wife, 55-year-old Margaret O'Leary-Joost; and their son, 18-year-old Daniel Joost, Monday night. The teen had autism and was enrolled in a transition program through the South West Cooperative.

David Joost's died of asphyxiation from hanging and his death was ruled a suicide, according to the Cook County Medical Examiner's Office. He also had incised wounds on his wrist. The deaths of his wife and son were ruled homicides. Margaret O'Leary-Joost died of strangulation and smothering and Daniel Joost was strangled, the office determined.

Police said after Margaret Joost, a crisis worker at Illinois Advocate Christ Medical Center, called in sick to work on Friday and did not show up on Monday, a co-worker went to her house in the 6600-block of Courtney Drive to check on her. The co-worker saw fluid that looked like blood coming from the garage door and called police.

Officers forced their way into the home just before 8 p.m. Police said there were no signs of a break-in.

Officers found Margaret Joost and Daniel Joost dead in their beds. David Joost was found in the garage.

"He had slit his wrists. He also appeared to have been hanging at some point and the car also appeared to have been left on and running," Anderson said.

Illinois State Police Crime Scene investigators processed the scene and found ligature marks around the necks of Margaret Joost and Daniel Joost.

Mary O'Mally, a neighbor, said she was aware the family had issues.

"Dave was very depressed. It was obvious. I mean he came to me with financial problems and depression. He was a closet alcoholic and his wife knew and he would talk to me about it sometimes," O'Malley said.

The family is survived by the couple's 20-year-old daughter, who attends Milikin University in Decatur in central Illinois.