Colt Gray is seen in a booking photo.

While searching the home of Apalachee High School shooting suspect Colt Gray, authorities found documents they believe he wrote that referenced previous school shootings, a law enforcement source familiar with the investigation told CNN.

The source said the texts were found in Gray’s bedroom and contained references to the 2018 massacre at Marjory Stoneman Douglas High School in Florida.

The discovery, which could shed light on a motive for the shooting, comes amid a new picture of Gray’s tumultuous family life in the years leading up to the deadly attack, revealed in a CNN analysis of court and law enforcement records, social media posts and an interview with his grandfather.

Gray’s parents have endured a bitter divorce and custody dispute in recent years. They’ve called each other out on the police, the family has been evicted from at least one home, and Gray’s mother has been arrested for defacing her husband’s car and drug possession, according to police records.

At the same time, Gray’s mother and maternal grandfather have accused Gray’s father of being verbally abusive to his family for years. The grandfather, who asked not to be named, said he never saw the shootings reveal any anger issues, but that the turbulent family life had affected the teen.

Detectives seeking to determine the suspected shooter’s motive are now looking at his family’s past dealings with state child protective services, the director of the Georgia Bureau of Investigation said Wednesday.

Attempts to reach the suspect’s parents for comment on Wednesday and Thursday were unsuccessful.

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