Federal investigators have discovered part of the cause of a 2016 explosion that killed seven people and injured dozens more.

They are also suing Kay Management, the company that runs the Flower Branch Apartments in Silver Spring.

Washington Gas was one of the defendants in the suit.

Authorities also announced that they have identified three people who were recovered in the debris.

Police also found that one person who was on their list of missing people is alive. He was not in the building at the time of the fire.

Officials have taken dozens of people to hospitals, and nearly one hundred residents are displaced from the Flower Branch Apartments.