The brother of one of the shooters in last week’s San Bernardino, California, massacre, which left 14 people dead, has been accused of domestic violence, the Los Angeles Times reported. The investigation into the allegation comes as a picture of the lives of the shooters, Syed Rizwan Farook and wife Tashfeen Malik, and their families is slowing being pieced together.

An unidentified woman reported a domestic disturbance at the home of Syed Raheel Farook, Syed Rizwan Farook’s brother, Saturday, and police conducted follow-up interviews Monday. The case was being reviewed by the Riverside County District Attorney’s office, and while no arrest has been made or charges filed, there was a possibility he could be charged with misdemeanor domestic battery, the LA Times reported.

During the divorce of Farook’s parents, domestic violence allegations were raised by Farook’s mother as well. She said in court papers her children saw abuse meted out by her husband, who she alleged pushed her toward a car and once drunkenly dropped a television set on her.

Raheel Farook is a U.S. Navy veteran, joining in 2003 after the U.S. invasion of Iraq, Reuters reported. He served on the USS Enterprise, were he worked as an information system technician.

Some who knew the brothers said that Raheel Farook was more “Americanized” than his brother. Others said Rizwan Farook took their Muslim faith far more seriously.

Investigators are still trying to piece together the events that led to the attack, with one friend of the attackers saying Rizwan Farook planned an earlier attack that was aborted, Fox News reported. Police are investigating the San Bernardino incident, in which the perpetrators walked into the Inland Regional Center and shot attendees of a holiday party in an apparent terror attack. The two were killed by authorities in a shootout following the initial attack.