The family of a Marine who was killed in an on-base shooting by an Afghan teenager in 2012 has sued the Defense Department, the Marine Corps and its retiring top general, alleging that they have systematically misled them about the case.

The complaint was filed Wednesday by the family of Lance Cpl. Gregory Buckley, who was killed along with Staff Sgt. Scott Dickinson and Cpl. Richard Rivera Jr. in a shooting Aug. 10, 2012, in Helmand province, Afghanistan. A fourth Marine sustained five gunshot wounds but survived.

The lawsuit, filed in U.S. District Court in New York, names Gen. James F. Amos, who retires as commandant of the Marine Corps on Friday; the Corps; the Defense Department; the Navy Department; and the Naval Criminal Investigative Service. It alleges that they have “inexplicably refused to conduct any investigation of the murders,” in which the shooter opened fire on the Marines with a Kalashnikov assault rifle while they were unarmed.

The Marine Corps does not comment on pending litigation, said a spokesman, Maj. John Caldwell.

The shooter, identified by the Marine Corps as Ainuddin Khudairaham, was convicted as a juvenile and sentenced to 7 1/2 years in confinement, the maximum under Afghan law for a minor, Marine officials said in July. That infuriated the Buckley family, who said they had been promised that the shooter, later found to be between 17 and 18 at the time of the shooting, as an adult.

The shooter worked for an Afghan police chief, Sarwar Jan, who had been removed as the police chief in another district in Helmand province in 2010 after Marines suspected he was providing supplies to the Taliban. A Marine who had worked with him in 2009 and 2010, Maj. Jason Brezler, sent a warning to deployed Marines about the police chief ahead of the shooting. Nevertheless, the police chief continued in his role.

Brezler sent classified information over an unclassified network to do so, and reported himself. The Marine Corps decided last year to separate Brezler from the service against his will, finding that he mishandled classified information inappropriately by sending the warning over an unclassified email account and kept other classified documents on his personal hard drive.

The lawsuit compares the shooting to the Sept. 12, 2012, attack on Camp Bastion, a major military installation in Helmand province. In that case, 15 insurgents penetrated the base’s external perimeter and launched a barrage of fire with grenades, machine guns and other weapons. Two Marines — Lt. Col. Christopher Raible, 40, and Sgt. Bradley Atwell, 27 — were killed, 17 other coalition members were wounded and nine U.S. aircraft were either destroyed or severely damaged.

In the Camp Bastion case, two major generals, Charles “Mark” Gurganus and Gregg Sturdevant, were forced into retirement as the results of a military investigation were released last fall. That stands in contrast to the insider attack against Buckley and his fellow Marines, the family alleges.

The Buckley family has not received a copy of the NCIS investigation, communication from the fallen Marine’s commanders, a copy of Buckley’s autopsy report, or clarification on how the Marine Corps looked into the case, they allege. The family added that they were told to submit a Freedom of Information Act request, but still have not received the information they seek.

“In short, these Gold Star families were sent on an unnecessary and emotionally traumatizing wild-goose chase for information the Marine Corps was legally obligated to provide in the first place, but is obviously determined not to provide,” said the suit, filed by Buckley’s father, Gregory Sr., and his aunt, Mary Liz Grosseto.

The family expresses frustration with Amos. They contacted his office several times beginning in January 2014 and allege that they were sent in circles by Marine officials rather than provided with answers.

“Had this ‘Who’s on First’ routine not been at the expense of a Gold Star family,” the suit alleges, “it would have made Abbott and Costello proud.”

The lawsuit compares the Marine Corps’ actions to the Army’s following the death of of Cpl. Pat Tillman, a former NFL football player who became an Army Ranger and sustained a fatal friendly fire gunshot wound in Afghanistan on April 22, 2004. The Tillman family later alleged that the Army hid that he died as a result of friendly fire.

The Buckley family blames the convicted shooter for the death, but alleges that the Marine Corps wants to keep quiet possible embarrassing gaps in security that allowed it to occur. The suit asks for the court to compel Amos and the government agencies named to disclose the information the Buckleys have sought. It also asks that the court require them to take steps to do so in other cases in the future.

“Gold Star families shouldn’t have to beg or sue to get the respect, information, and assistance to which they are legally and morally entitled,” the Buckley family’s lawyer, Michael Bowe, said. “This is a sad and shameful day.”