When a Maryland State Police trooper was killed in June — the 42nd in the department’s 90-year history — Shaft S. Hunter gave his family a solemn look. “It’s just a part of the job,” he said.

On Saturday, nearly a year later, Hunter became the 43rd state police officer to die in the line of duty when his police car slammed into a tractor-trailer on Interstate 95. Officials think Hunter was pursuing a speeding motorcyclist.

Hunter, 39, landed his dream job with the state police 11 years ago, after a stint with the Marines, from which he had been honorably discharged as a first lieutenant. He made his mark quickly with the state police, executing drug busts that earned respect from his colleagues.

Hunter kept a demanding schedule, moonlighting as a security guard at restaurants, stores and movie theaters to provide for his six children. He spent his days making arrests — once pulling a half-million dollars in heroin from a suspect’s car — and then showing up hours later to stand guard at a Denny’s restaurant or the Magic Johnson movie complex in Largo.

“Trooper First Class Hunter was an outstanding trooper who was known for his dedication to duty,” Col. Terrence B. Sheridan, the Maryland State Police superintendent, said at a news conference Saturday.

Hunter’s death was a rare loss for the department and came at the end of National Police Week, which honors the more than 19,000 officers across the United States who have died in the line of duty.

Witnesses told investigators they saw Hunter’s marked cruiser pursuing a speeding motorcycle about 2:40 a.m. Saturday. The cruiser struck a tractor-trailer that was parked along I-95 South near the entrance of a rest stop south of route 32 in Howard County. Hunter was pronounced dead at the scene.

The motorcyclist, who was described as wearing a white helmet, had not been located. Police did not release any additional information Sunday about the crash.

Hunter lived and breathed law enforcement, said Cheryl Shymoniak, grandmother of one of Hunter’s sons. His children were ages 4 to 19.

“He lived for his job and his family,” Shymoniak said. “He was born to wear a uniform.”

When friends complained to Hunter about getting speeding tickets, Shymoniak said, he crossed his arms and laughed. “You don’t speed in Maryland,” he would say.

Known as a stern officer while on the job, Hunter, who was from Bridgeport, Conn., was remembered by friends and family for his sense of humor and generosity. When his police dog, Bear, was retired from the force, Hunter took it home to live with his family. He enjoyed spending free time with his children and watching the Dallas Cowboys.

Hunter’s colleagues, some of whom created a Facebook page in his memory, are still awaiting closure after the slaying of a state trooper last year.

On June 11, Trooper 1st Class Wesley W. Brown was shot and killed while working a part-time security job at an Applebee’s restaurant in Forestville. Prince George’s County police have filed charges against two men in the case. Anthony Andre Milton II pleaded guilty to a charge of accessory to murder. Cyril Cornelius Williams, who faces first-degree murder charges, is awaiting trial.

In neighboring Virginia, 56 state police officers have died since that department was established in 1932.