An Army sergeant from Providence is charged with complicity in the murder of four prisoners after a combat patrol in Iraq in 2007.

Sgt. Charles L. Quigley, 28, a lifelong city resident whose parents live in Mount Pleasant, is accused of knowing in advance that some of his fellow soldiers intended to kill the Iraqi prisoners, and he is charged with conspiracy to commit premeditated murder.

“These charges are not viable. He’s not guilty,” Pamela Quigley, the sergeant’s mother, said last night in an interview in the living room of the cottage his parents share.

It would be “very out of character for Charlie to have done [what] he’s accused of,” she said. “We’re very proud of Charlie.”

The Army alleges that three soldiers handcuffed and blindfolded the Iraqi prisoners, who were suspected fighters, executed them with pistol shots to the head and dumped their bodies in a Baghdad canal between March 10 and April 16, 2007.

The executions allegedly were retribution for two combat deaths suffered by the soldiers’ unit. Military law forbids harming enemy combatants who are in custody

Four more soldiers including Quigley knew what happened but kept quiet, according to the initial charges.

Pamela Quigley, 59, a semiretired lawyer who used to work as an assistant solicitor for the City of Providence, and her husband Dennis, 59, a letter carrier for the U.S. Postal Service who is retired from many years of military service, mostly stay in touch with their son by telephone. They have a flight booked to Germany to be with him when he is scheduled to be court-martialed next month on a military base in Vilseck, Bavaria.

Her son initially was scared by the charge against him, she said, but now seems resolute on winning acquittal.

“He’d like to have the whole thing over with,” she said. The charge he faces potentially is punishable by a sentence of life without parole in federal prison.

Charles Quigley’s military lawyer, Capt. Samuel Gregory, has said that his client had little or no knowledge of the killings. At his own expense, Quigley has also hired a civilian lawyer with extensive experience in military justice.

Quigley told his parents that he saw nothing of the nighttime incident and that he was sitting in a Humvee 50 meters away. But Pfc. Jonathan Schaffer testified at an Article 32 hearing last year that he was with Quigley, that the prisoners were led away by others and six or seven shots were heard.

“Quigley was with us. He looked nervous and shocked,” Schaffer testified.

An Article 32 proceeding is the military equivalent of a civilian grand jury.

After the hearing, in August, according to Mrs. Quigley, the presiding officer recommended that no criminal charge be brought against her son. Stars and Stripes, a newspaper that serves the military, reported that Charles Quigley wore a wire to help gather evidence against others implicated in the crime.

But a general rejected the hearing officer’s recommendation, Mrs. Quigley related.

“It’s almost, if we throw enough spaghetti [against the wall], something will stick,” Dennis Quigley said of the case against his son.

Charles Quigley enlisted in the Army in 2002 and underwent basic training at Fort Benning, Ga.

“After September 11th, that’s when he started seriously thinking about the military,” Mrs. Quigley said.

The Quigleys sent their son to Holy Ghost parochial school on Federal Hill as a child, and in the late 1990s, he graduated from Hope High School, where he had participated in the music program and played bass guitar. His mother described him as a person with “an excellent sense of humor” who enjoys role-playing games on the Internet.

He attended the Community College of Rhode Island for a while, but in his father’s words, he “got restless” and went into the Army. There he gained confidence and flourished, by his parents’ account, and he became a squad leader. In 2003, he shipped out to Iraq, where he served two tours of duty for a total of 27 months.

“When you see the pictures of them going into the houses in Iraq, that’s my son,” his mother said.

“That’s why I have white hair,” she added.

The three soldiers who are charged with doing the actual killing are Sgt. First Class Joseph P. Mayo, 27; Sgt. Michael P. Leahy Jr., 26, of Lockport, Ill., the company’s senior medic and an acting squad leader; and First Sgt. John E. Hatley, 40. The Army has not provided hometowns for Mayo or Hatley.

Also initially charged in the alleged conspiracy were Specialist Steven Ribordy, 25, of Salina, Kan.; Specialist Belmor Ramos, 23, of Clearfield, Utah; and Staff Sgt. Jess Cunningham, 27, of Bakersfield, Calif. Ribordy and Ramos last year pleaded guilty to conspiracy to commit premeditated murder — they stood guard during the slayings — and were sentenced to prison. Both men agreed to testify against Leahy and others.

The Army last week dropped the charge against Cunningham, but he is expected to be a prosecution witness.

Leahy’s court-martial began yesterday before a jury of seven men and two women — officers and enlisted personnel — in the Rose Barracks Courthouse on the Vilseck base.

All of the soldiers in the case were with the 1st Battalion, 18th Infantry Regiment, 2nd Brigade of the 1st Infantry Division in Iraq, which is now part of the 172nd Infantry Brigade.