BEIRUT, Lebanon — A Skype call captured the artillery barrage that killed an American war reporter, Marie Colvin, on Feb. 22, 2012: thundering shells, people rushing for cover, screams of pain. Then a shout: “She’s dead.”

Later that day, according to a Syrian defector, a military intelligence officer who had ordered the surveillance and shelling of journalists expressed grim satisfaction: “Marie Colvin was a dog and now she’s dead. Let the Americans help her now.”

The call and the defector’s account are among a trove of materials that lawyers for Ms. Colvin’s family have presented to a judge in Washington in a wrongful-death suit they filed in 2016 against the Syrian government and nine Syrian security officials. The judge, Amy Berman Jackson of the Federal District Court, partly unsealed the fillings on Monday.

The lawyers say that the records provide the strongest evidence to date that Syrian forces led by President Bashar al-Assad targeted foreign journalists who were chronicling the mounting horrors in Syria, and Syrian civilians helping the reporters to gather information.

The filings, nearly 200 in total, are part of a far larger cache of some 700,000 records that have been smuggled out of Syria by defectors, activists and others and meticulously collected by the Committee for International Justice and Accountability, which wants to build war-crimes cases against the Syrian government.

“These documents allow us to reconstruct the broader policy planning that identified media workers as targets from very early on in the conflict,” said Scott Gilmore, a lawyer for the Colvin family. “They also lay out the command and control structure and reveal things that even Syria experts don’t know.”

It is impossible to independently verify the documents, but numerous experts, including diplomats, government officials and academic researchers, have vouched for the work of the committee, which was founded by William H. Wiley, a Canadian war-crimes investigator.

Ms. Colvin, a native of Long Island who was 56 when she died, was a veteran observer of numerous conflicts and wrote for The Sunday Times of London. Another journalist — Rémi Ochlik, 28, a French freelance photojournalist — died in the same attack that killed her, in the besieged city of Homs.

Syrian officials have contended that journalists operating outside of government-controlled territory, as Ms. Colvin did, violated the law. “It’s a war and she came illegally to Syria, she worked with the terrorists, and because she came illegally, she’s been responsible for everything that befell on her,” Mr. Assad told NBC News in 2016, denying that Ms. Colvin had been targeted.

The Syrian government has not responded to the Colvin family’s lawsuit.

The documents appear to reveal the workings of the Central Crisis Management Cell, a committee reporting to Mr. Assad that was created to counter the uprisings that broke out across Syria in 2011.

In early 2012, witnesses described indiscriminate, non-targeted shelling of Baba Amr, a neighborhood in Homs where opposition activists had set up a media center to communicate with journalists.

One document shows how military and security forces intercepted communications between journalists and the activists. Intelligence officers passedon information about a journalist for Al Jazeera to a military special forces unit with the instruction, “Take the necessary measures.”

Lawyers are also citing several sworn witness accounts. One is from a defector, whom the lawyers code-named Ulysses, who chronicled the contemptuous remarks about Ms. Colvin made by the intelligence officer, Maj. Gen. Rafik Shahadah.

Ulysses, who remains in exile, told the lawyers that the military had ordered an attack on Ms. Colvin and her colleagues as part of a broader effort — directed from the top and laid out in the documents — to track, arrest and target demonstrators, coordinators and “those who tarnish the image of Syria” by talking to journalists and other foreigners.

Ulysses also testified that Syria’s powerful intelligence chief, Ali Mamlouk, received information from “friendly Lebanese officials” that foreign journalists were crossing the Syrian border to reach Homs and instructed the commander of the military-security committee in the central Syrian city to “capture the journalists” and “take all necessary measures.” Ulysses said that phrase customarily “authorized killing if needed.”

Two additional witnesses appeared to corroborate such a strategy.

One is Abdel Majid Barakat, a former data manager of the Central Crisis Management Cell who eventually defected.

Mr. Barakat saw documents that identified Syrians providing information to journalists as a top national security threat demanding a lethal response. He said he heard discussions of plans to fabricate evidence of rebels attacking civilians. He quit when he concluded there was no intention of reform, fleeing Syria with USB drives and paper documents bandaged to his torso under his clothes. (He defected several weeks before the journalists were killed.)

Another witness — Anwar Malek, an Algerian member of an Arab League monitoring mission — said he quit the mission after coming to believe that members were acting as agents for the government and removing evidence of government attacks on civilians, including the case of a 5-year-old boy killed by a sniper, from reports.

Mr. Malek described conversations in Homs in January 2012 with a member of the crisis committee, Deputy Defense Minister Assef Shawkat, Mr. Assad’s brother-in-law. He said Mr. Shawkat told him that it was necessary to kill civilians to defeat “the terrorists,” that “he would have been able to destroy Baba Amr in 10 minutes if there were not any video cameras” and that foreign journalists reporting from Baba Amr were “agents” of Israel and other countries, who should be targeted.

“‘For us, these are terrorists,’” Mr. Malek quoted him as saying. “They are targets for our military services and our security forces.”

Mr. Malek added that when Mr. Shawkat learned he had visited the media center, he pressed him to disclose its exact location; Mr. Malek demurred.

Soon after, Mr. Malek concluded that the mission was compromised and resigned. He said he received a death threat over the phone in his Homs hotel room, and his convoy to Damascus was shot at. The government blamed rebels, but Mr. Malek believed the attack was staged by the government.

Syrian activists brought in Ms. Colvin and a British journalist, Paul Conroy, through a mile-long, four-foot-wide water pipe. Soon after, Ulysses said, an informant told intelligence officials that the journalists were at the activists’ media center and described its rough location.

The two reporters agreed the shelling was “merciless” and “dire,” the most intense they had ever faced, Mr. Conroy told the lawyers. On Feb. 21, Ms. Colvin issued a live report from the media center, giving a searing account of the plight of civilians.

That, Ulysses said, allowed the government to use surveillance equipment to pinpoint the location, matching the informant’s report. He recalled the deputy head of the Computer and Signals Section of Branch 261 of the military intelligence department in Homs saying, “There was a broadcast tonight from the same location.” Then the official added: “The boss is very happy.”

Among those overseeing the operation, Ulysses said, was Maher al-Assad, the president’s brother, commander of the powerful Fourth Division of the Republican Guard and a member of the crisis-management committee.

The next morning, Mr. Conroy said, the pattern of shelling changed. Instead of the saturation waves of shelling across the whole neighborhood, strikes alternated on each side of the house hosting the media center, getting closer each time. He recognized it as a technique called bracketing, or “walking in”: A forward observer reports back how close the a shell hits to the target and corrections are made.

The house then took direct hits. On the Skype call, which involved Syrian media activists, as well as a journalist from Al Jazeera, Mr. Conroy can be heard calling: “I can’t move! I need a tourniquet.”

Mr. Conroy stumbled outside and saw Ms. Colvin and Mr. Ochlik dead.

“Her head was buried in concrete and her feet were buried in rubble,” he said.

The others eventually made it back to Lebanon.

Back in Homs, General Shehadeh was soon promoted to head the military intelligence department for the whole country. The leader of a pro-government militia charged with developing informants inside Baba Amr, Khaled al-Fares, received a black Hyundai Genesis.

It was a reward, Ulysses said, from the president’s brother.