A 22-year-old Baltimore man, Maurquise Emillo James, has been charged with first-degree murder in the Feb. 14 killing of 87-year-old philanthropist Robert Fuller Jr. at a Potomac nursing home where James worked.

Fuller, a retired Navy Reserve officer, was found shot in the head, and police say James had access to the facility and allegedly used a disguise—including a mask and wig—during the attack.

Investigators have not determined a motive, though surveillance footage and tips linked James to the crime, and evidence suggested it may have been an inside job.

James was later charged with attempted first-degree murder and other offenses after allegedly shooting at a Maryland state trooper during a traffic stop; the trooper was unharmed, NBC News has reported.

Police matched shell casings from the trooper shooting to the weapon used in Fuller’s murder, solidifying the connection.