(CNN) -- A Marine officer on Tuesday became the seventh person cleared of charges related to the deaths of 24 Iraqi civilians in Haditha, Iraq.
A military judge dismissed charges against Lt. Col. Jeffrey Chessani, who was charged with dereliction of duty and violation of a lawful order for failing to report and investigate the incident.
Col. Steven Folsom found that a four-star general overseeing the case was improperly influenced by an investigator probing the November 2005 shootings
"Unlawful command influence is the mortal enemy of military justice," said Folsom, reading aloud from previous case law, The Associated Press reported.
Chessani was the highest ranking officer involved in the Haditha incident. Twenty-four civilians were killed in what military prosecutors said was a house-to-house rampage by Marines after a roadside bomb killed their comrade, 20-year-old Lance Cpl. Miguel Terrazas.
A statement from the Marine Corps originally blamed the Iraqi deaths on the roadside bomb, triggering a parallel investigation into how commanders handled the incident.
Charges have already been dropped against Capt. Lucas McConnell, commander of the Marine company involved in the killings; Capt. Randy Stone, who had been accused of failing to properly report the facts; Maj. Gen. Stephen T. Johnson, former commanding general of II Marine Expeditionary Force.
Charges were also dropped against Lance Cpl. Justin I. Sharratt, one of four initially charged with murder. Another Marine charged with murder, Sgt. Sanick Dela Cruz, had charges dropped in exchange for his testimony.
First Lt. Andrew Grayson was acquitted earlier this month by a military jury.
Grayson was accused of attempting to cover up the killings. He was charged with two counts of making false statements to officials, two counts of trying to fraudulently separate from the service and one count of attempting to deceive by making false statements.
The jury deliberated for five hours before finding Grayson not guilty on all counts.
Staff Sgt. Frank Wuterich is now the only Marine facing charges in the Haditha incident. Charges against him include voluntary manslaughter and dereliction of duty.