A NASA employee was charged Wednesday with murdering his neighbor, a Maryland National Guardsman, with whom he’d fought for years over loud music, dog poop, and guests, according to police and family members.

Michael Hetle, 52, faces several charges, including second-degree murder and the use of a firearm in the commission of a felony, in the slaying of his 24-year-old neighbor Javon Prather, Fairfax County police told The Daily Beast on Thursday.

Hetle, a former police officer who was previously involved in the controversial fatal shooting of an unarmed Latino man in 2001, is currently being held without bond at the Fairfax County Adult Detention Center.

Authorities said Prather, a specialist with the 175th Infantry Regiment of the Maryland National Guard, was found at around 5 p.m. with an “apparent gunshot wound.” Although officers “immediately rendered first aid,” Prather was pronounced dead at the scene.

“He served as an infantryman for nearly four years & was awarded the Army Reserve Component Overseas Training Ribbon & the National Defense Service Medal and Army Service Ribbon,” the Maryland National Guard tweeted on Wednesday evening. “Rest easy, brother.”

A police spokesperson declined to provide The Daily Beast with a possible motive for the shooting, saying “detectives are continuing their investigation into the events leading up to the shooting.” But Shavon Prather, the 24-year-old’s mother, told The Washington Post that Hetle had a long-standing feud with her son and his wife.

They sometimes argued over loud music and house guests, she told NBC News.

Prather said that the feud had become so bad that at one point her son had considered selling their home. Authorities had been called to the neighborhood several times, she added.

“[Hetle] would call the HOA and say there was dog poop in their backyard,” Shavon Prather told the Post, referring to the neighborhood’s homeowners association. “He would call and complain when they put out the trash. Anything he could do to scold them and to get them in trouble.”

Maryland Gov. Larry Hogan expressed his condolences on Wednesday, tweeting that he was “deeply saddened” by the news of Prather’s death.

“The First Lady and I ask all Marylanders to join us in sending our heartfelt prayers to Javon’s family, friends, & to all those who loved him,” Hogan said.

In a statement to The Daily Beast, NASA confirmed Hetle’s employment, stating that he was “a career civil servant who works at NASA Headquarters in Washington in the agency’s Enterprise Protection Program.”

In his role, Hetle “is responsible for the business operations of the directorate and the executive staff, and supports the associate administration in coordinating the reviews of all nationwide and international NASA aeronautics related research programs,” according to an online biography on NASA’s website.

Before joining the space organization, Hetle worked at the Department of Homeland Security as a director, the Department of Defense, and was a 20-year veteran of the Navy, the biography states.

Hetle also served as a police officer in Bellevue, Washington, from 1994 to 2001, a department spokeswoman told The Daily Beast. During his time as a cop, he was involved in two fatal shootings, in 2000 and 2001, while on the job.

During the first incident, Hetle shot and killed a bank robbery suspect who was armed. In the second, he fatally shot 24-year-old Nelson Martinez-Mendez, an unarmed Guatemalan man while responding to a report of domestic violence at his home.

While he was cleared of any wrongdoing in both incidents, the city of Bellvue reached a $75,000 settlement with Martinez-Mendez’s family in 2005 for the shooting outside his apartment complex, the Seattle Times reported at the time.