Military prosecutors presented new and detailed evidence Thursday that they said showed that Pfc. Bradley Manning collaborated with Julian Assange, the founder of the anti-secrecy Web site WikiLeaks, in stealing more than 700,000 documents from classified computer systems and publishing them on the Internet.

Assange came under grand jury investigation, possibly for conspiracy, after WikiLeaks publicized secret U.S. documents, roiling U.S. diplomatic relations and turning Manning, for some, into a whistleblowing hero.

Manning’s defense attorney, David E. Coombs, accused military prosecutors of “over-charging” in the case in an effort to obtain a plea agreement and gain the former intelligence analyst’s cooperation in a separate, federal case against Assange.

In just over an hour of closing arguments at a pretrial hearing, the prosecutors disclosed three new excerpts of chat logs taken from Manning’s personal Macintosh laptop. In one, he allegedly asks Assange for help in figuring out a password. In another, he allegedly tells Assange “i’m throwing everything i’ve got on’’ Guantanamo detainee reports “at you now” and estimates the “upload is about 36 pct” complete.

To which Assange replied, according to the prosecutors’ PowerPoint presentation, “OK . . . great.”

Baher Azmy, an attorney for Assange with the Center for Constitutional Rights, said the evidence is speculative. “We have no access to and cannot review or see the government’s evidence,” he said. “We do not know if it is reliable.”

Thursday’s dramatic proceedings brought to a close a seven-day hearing at Fort Meade to determine whether Manning will face a court-martial and under what charges. Coombs seemed to concede that the court-martial will proceed, making an impassioned plea that the charges Manning might face be reduced from 22 to three. He argued that the maximum sentence should be not the death penalty or life in prison but a maximum of 30 years behind bars.

The military will render a decision early next year on whether a court-martial will take place.

In a 20-minute summation, Coombs argued that Manning, now 24, was struggling with a gender-identity crisis so severe that he was unable to function even before he deployed to Iraq in October 2009. Coombs said Manning’s superiors repeatedly failed to act on signs of his distress.

Coombs read an anguished e-mail from Manning in which he told a superior about his “problem” with gender identity. “I thought a career in the military would get rid of it,” he wrote.

Coombs also argued that Manning was young, idealistic and “with a strong moral compass” — someone who believed “you can change the world.”

He argued that WikiLeaks’ posting of more than 250,000 diplomatic cables, and voluminous databases of Iraq and Afghanistan military field reports, has not caused harm to the United States, and that the government’s claim that “there’s been extreme harm . . . is an overreaction.”

“The sky has not fallen,” Coombs said. “The sky is not falling. And the sky will not fall.”

The prosecution countered that Manning was a bright soldier, an analyst “whom we trained and trusted” to use multiple intelligence systems to aid battlefield commanders. “He used that training to betray our trust,” Capt. Ashden Fein said.

Manning began his campaign to help WikiLeaks, Fein said, within two weeks of arriving in Baghdad. Over a six-month period he “indiscriminately and systematically harvested over 700,000 documents’’ from the secret-level classified network. He did so, Fein said, using as a guiding light WikiLeaks’ list of “Most Wanted Leaks,” which had been published on the Internet.

Prosecutors said the chat logs between Manning and Assange came from Manning’s personal computer, which a forensic examiner testified this week were authentic. They show an interlocutor whose user name, prosecutors said, is an alias for Assange.

In a March 8, 2010, chat, Manning asked Assange for help in cracking a password so he could log onto the classified computer anonymously, Fein said.

“Any good at IM-Hash cracking?” Manning asks.

“Yes,” is the reply. “We have rainbow tables for IM,” the interlocutor says, citing a tool that can be used to decipher passwords.

Manning sends a string of numbers.

“Passed it on to our guys,” is the reply.

On March 15, prosecutors said, WikiLeaks published another document that Manning provided, a classified 2008 Army counterintelligence report that discussed the potential for leaks of material to WikiLeaks that could result in an advantage to foreign enemies.

Three days later, prosecutors said, Manning told Assange in a chat that a New York Times article cited an Army spokesman “confirming the authenticity” of the report.

Assange allegedly asked: “Yes?”

Manning replied: “Hilarious.”

Manning transfered classified information “knowing” that U.S. enemies, including al-Qaeda, would have access to the information, Fein said.

He showed an al-Qaeda video clip in which a spokesman, over flashes of the WikiLeaks home page, says followers should not enter battle “before taking advantage of the wide range of resources available on the Internet.”

The material disclosed Thursday not only potentially strengthens the military’s case against Manning but also aids civilian prosecutors in their effort to bring a case against Assange, experts said. The Justice Department has said it has an active grand jury investigation against Assange and WikiLeaks. Lawyers representing him and the group have been in the Fort Meade courtroom all week.

Assange’s apparent role in helping Manning gain access to classified information “would get you closer to the point of charging Assange” with conspiracy to violate the Espionage Act, said a former federal prosecutor whose firm did not authorize him to speak publicly on the matter.

As he closed, Coombs repeated his appeal that Manning, who grew up in small-town Oklahoma and thought the Army would give him a future, acted out of pure motives.

“History will ultimately judge my client,” he said, and reprised a quote from Martin Luther King Jr. “An individual who breaks a law” that conscience tells him is unjust, Coombs said, and who risks prison to arouse the conscience of the community is in reality expressing the “very, very highest respect for the law.”