NORFOLK, Va. — He was a good kid from a humble family who seemed always to want to please his teachers and coaches. He got decent grades and played football and wrestled while in high school in Hagerstown, Md. He wanted to be a cop.
After graduation, Mark Mayo chose his path. He enlisted in the Navy, left home and trained to become a master-at-arms - a military police officer.
Soon he was in Bahrain, then Spain, then Norfolk.
He died here, at age 24, doing a job he loved.
The Navy on Wednesday identified Mayo as the sailor who was killed late Monday by a civilian truck driver who passed through security at Norfolk Naval Station, boarded the pierside destroyer Mahan, and wrested a gun from a female sailor standing guard on the deck.
Mayo, who was assigned to the base's security department, saw the struggle and rushed to intervene. He was shot while pushing the guard to the ground in an effort to protect her, said Capt. Robert Clark, Norfolk Naval Station's commanding officer.
"It was incredibly extraordinary," Clark said. "He gave his life for hers."
As other sailors came to help, the civilian was shot and killed.
"Petty Officer Mayo's actions were nothing less than heroic," Clark said. "He selflessly gave his own life to ensure the safety of the sailors on board."
Among other new information, Clark said the assailant - whom officials have identified but not named publicly - should not have been on the base that night. At the gate driving a tractor-trailer cab, he used a valid credential called a TWIC card, issued to transportation and maritime workers. But Mayo's shooter also should have had a legitimate business reason for coming in, and Clark suggested he didn't.
"On this particular evening," Clark said, "he did not have authorization to be on my base."
Clark said the Navy is launching a second investigation - on top of one being conducted by the Naval Criminal Investigative Service - that will examine how the shooter made it through the gate as well as another checkpoint before the pier.
Mario Palomino, NCIS's agent in charge, said investigators haven't determined a motive. They don't think the assailant, who Palomino said did not work for the Defense Department, knew anyone on the Mahan.
And they don't think the attack was planned.
"We have been able to rule out any additional threat to the Navy," Palomino said. "We have ruled out any link to terrorism."
He said that before Mayo died, he shot back.
In all, Palomino said, "numerous pistol rounds were fired."
The Mahan's commanding officer, Cmdr. Zoah Scheneman, made brief statements Wednesday near the ship, with yellow police tape in the background.
"The events of Monday affect us all," Scheneman said.
Navy officials informed Mayo's family Tuesday.
Speaking to the Herald-Mail newspaper in Maryland, Mayo's mother, Sharon Blair, said her son was born in Washington, D.C., and moved with his family to Hagerstown in 1998.
She said he always wanted to work in law enforcement.
Randy Longnecker, Mayo's former guidance counselor at Williamsport High School, recalled Mayo as a kind, easygoing student who rarely missed class and earned good grades.
Eric Michael, a former Williamsport assistant principal, said coaches and teachers appreciated Mayo's good attitude and liked to call him by the nickname "Marky Mark."
"He always wanted to make sure he was doing the right thing," Michael remembered. "He liked athletics and being part of a team."
Said Longnecker: "He must have fallen in love with the Navy."
Mayo enlisted four months after graduation, in October 2007. He'd been in Norfolk since May 2011. He was a petty officer second class.
Devrine Jones, a former Navy master-at-arms, or MA, served with Mayo in Bahrain in 2008.
He said sailors liked to work with Mayo because he was fun, easy to be around and happy doing his job - duties such as standing guard and inspecting vehicles coming onto the Bahrain base.
"He never had an attitude," Jones said. "He loved being an MA."