A Toronto man convicted in the murder of his four-year-old son is facing a steep prison sentence after a ruling Thursday. 

Joel Roberto was sentenced to life in prison with no chance of parole for 18 years after a jury found him guilty in July of second-degree murder.  

His partner, Ravyn Colley, was found guilty of first-degree murder in the case. She was automatically sentenced to life in prison with no chance of parole for 25 years last July.    

Their son, Jaelin Roberto Colley, was found without vital signs after police responded to a call at the couple's home in the Finch and Leslie area on Oct. 13, 2014.

Crown documents in the case say the call came from the child's father who claimed his son fell down the stairs two days earlier. Roberto told the police dispatcher that his son was breathing.

But when firefighters arrived, Jaelin was lying on his back on the floor in the middle of the room, without a pulse.

Blunt force trauma, aspiration of vomit

The documents also say that the four-year-old was cold to the touch and had blood pooling at the back of his head.

A postmortem examination found that Jaelin died from blunt force trauma while choking on his vomit. Severe malnutrition was also a contributing factor. He weighed 27.6 pounds.

The postmortem also found that Jaelin had multiple injuries all over his body and had been dead for hours before the call was made. 

The Crown argued that Colley and Roberto were frustrated over the child's toileting accidents.

First responders at the scene said Jaelin's mother was not present while they were treating him. They only became aware that Colley was in the house as they were getting ready to leave.

The couple were arrested at the scene and charged with failing to provide the necessaries of life. Those charges later escalated to first- and second-degree murder.