Charles Severance talks with an attorney on March 19. (Katherine Frey/The Washington Post)

The man who is charged in the fatal shootings of three of Alexandria’s most well-known residents over the past decade was driven to kill by a child custody decision that went against him and a hatred for what he termed the city’s “enforcement class,” according to papers filed by prosecutors Thursday.

In writings that were seized by authorities, Charles Severance, 54, expressed anger over a court decision to take his son from him and described a political doctrine that he felt allowed him to kill members of the “status quo utopian elite,” the filings said. Prosecutors wrote that Severance “chose to murder Alexandrians to accomplish his un­or­tho­dox political goals” and did so in a calculated way.

“These are not murders borne of greed or opportunity,” they said. “Instead, they resemble assassinations — a term used on various occasions by the defendant in his writings.”

The court filings — prosecutors’ responses to Severance’s legal maneuvers in the case — spell out in more detail than before what investigators believe spurred the onetime political candidate to kill. They also describe some of the evidence investigators believe connects Severance to the high-profile crimes.

Severance is charged in the February slaying of music teacher Ruthanne Lodato, the November 2013 fatal shooting of regional transportation planner Ronald Kirby and the 2003 killing of real estate agent Nancy Dunning. Authorities have said all three were gunned down in daylight in their homes, within two miles of one another, by a killer who left no sign of forced entry.

Severance, who had a felony record and a history of unusual behavior, was first taken into custody on a weapons charge this year in West Virginia, and his defense attorneys have complained about the circumstances of that arrest. They also have asked that he face a separate trial in Dunning’s death, which is older than the others.

But by prosecutors’ account, the killing of Dunning was the first in what would become a chilling series.

Prosecutors wrote that they believe Severance is the man who followed Dunning inside a Target store in the Potomac Yard shopping center shortly before she was killed. They wrote that they intend to show jurors store surveillance images and images of Severance during that time period so they “will be able to assess how closely parallel they are.”

Police had released the surveillance images in hopes of producing leads, but those leads apparently did not take them to Severance. According to the court filings, investigators eventually connected Severance to that killing — as well as Kirby’s and Lodato’s — through a combination of forensic evidence, witness statements and Severance’s writings.

Those documents, prosecutors wrote, show Severance to be “intelligent, well-read, calculating, and focused on violence.” They said Severance’s writings “comprise the defendant’s political manifesto and explain the defendant’s reasons and motivations for these offenses.”

Prosecutors wrote that the ammunition used in the killings — .22-caliber hollow-point rounds — was strikingly similar, though a different gun seemed to be used each time. They wrote that Severance was fascinated with that ammunition. Two experts would testify that “the only crimes in which they have ever observed this combination of make, model, and caliber of ammunition used are these three murders,” the prosecutors said.

Prosecutors also revealed Thursday a new detail of the Lodato slaying: After she was shot, Lodato told someone that her attacker was a stranger to her.

Separately, they alleged that Severance tried to escape confinement in West Virginia by taking a rope of knotted bedsheets into the recreation yard and trying to measure the jail fence.

A hearing in the case is scheduled Thursday. Joe King, one of Severance’s defense attorneys, and Alexandria Commonwealth’s Attorney Bryan Porter declined to comment for this article.