A lawyer representing a Montreal family accused of murdering three girls and a female relative is expressing concern for his clients' safety after they were allegedly beaten and subject to death threats in jail.

The Kingston Whig-Standard reports that Hamed Shafia, 18, was assaulted by other inmates, but wasn't seriously hurt, at the Quinte Detention Centre in Napanee.

His mother, who is being held in a women's section of the jail, has also been subjected to screams of "baby killer."

The teen and his father have since been moved to isolation, according to the report.

The three family members were arrested last week on four counts of first-degree murder in connection with the deaths of three teenage girls and their father's first wife, whose bodies were found in a car submerged in the Rideau Canal in Kingston.

Their next court appearance is scheduled for Aug. 6.