PHOENIX — Jared Lee Loughner was polite and cooperative as authorities began their hours-long initial interview of the man who went on a shooting rampage outside a Tucson grocery store, killing six people and severely wounding former Rep. Gabrielle Giffords and 11 others, according to detailed police reports released today.

The conversation as Loughner sat in restraints in an interview room was mainly small talk. Little was said over the first four hours.

The roughly 2,700 pages of documents have been kept private since the January 2011 attack. The Pima County sheriff’s department released the records from the investigation into the shooting outside a Safeway where Giffords was hosting a meet-and-greet with constituents.

The documents include transcribed interviews with witnesses and various police reports, and provide new insight into how the shooting occurred.

News organizations seeking the records were repeatedly denied the documents in the months after the shooting and the arrest of Loughner, 24, who was sentenced in November to seven consecutive life sentences, plus 140 years, after he pleaded guilty to 19 federal charges.

U.S. District Judge Larry Burns had prevented the sheriff’s department from releasing the records in response to a request from The Washington Post, ruling in March 2011 that Loughner’s right to a fair trial outweighed whatever disclosures might be authorized under state law.

Last month, Burns cleared the way for the release of the records after the Star Publishing Co., which publishes the Arizona Daily Star in Tucson, had sought their release. The judge said Loughner’s fair-trial rights are no longer on the line now that his criminal case has resolved.

Loughner’s guilty plea enabled him to avoid the death sentence.

The Star said it wanted the records because they contain information about how a mass shooting occurs, including how long it took Loughner to fire gunshots — an issue raised by some advocates in the debate over high-capacity pistol magazines.

The Tucson newspaper argued that the records are critical in the national debate over whether such shootings could be prevented by armed resistance, whether a mass shooting occurs too quickly to be stopped and whether people with mental illnesses should be prohibited from getting guns.