Shortly after 10:30 p.m., base and Prince William County police responded to a 911 call, officials said, and the base immediately went into lockdown.
Law enforcement personnel discovered the bodies of Sgt. Lopez, a machine-gunner from Pacifica, Calif.; Cpl. Jacob Wooley, 23, a radio field operator from Guntown, Miss.; and Lance Cpl. SaraCastromata, 19, a warehouse clerk from Oakley, Calif.
Sgt. Lopez, a father of two daughters, was a tactics instructor at the base’s Officer Candidate School. He had served in the Marines for more than six years, and had deployed to Iraq and Afghanistan.
The shooting occurred at Taylor Hall, a residential barracks, base commander Col. David W. Maxwell said Friday.
Family members also are trying to figure out what happened.
“When I heard the news, my heart sank and I felt like I couldn’t breathe, I was trembling so bad,” said Yolanda Linares, a cousin of Cpl. Castromata. “We are all just still in disbelief. We just want her back with us.”
Ms. Linares described her cousin as “a very bright woman [who] always had a beautiful smile on her face.”
“She was always happy, loving, caring, a great person to have had in your life,” Ms. Linares said. “She was there when you needed her.”
“We were all really proud of her for making such a big decision; she was extremely passionate about it,” she said. “She took charge of her life and for her to become a Marine, we all couldn’t be more proud of her for having the strength, courage and heart to serve and protect this country.”
Investigators are trying to figure out a motive for the shooting, and a “love triangle” is speculative at this time, according to Marine Corps officials.