TUCSON — The parents of Jared L. Loughner, the man who killed six people and wounded 13 others during a meet-and-greet event hosted by former Representative Gabrielle Giffords in 2011, told the authorities after the mass shooting that they had become so concerned about their son’s strange behavior in the previous months that they had taken away his shotgun, insisted he get psychological counseling and had even begun to disable his car so that he could not go out at night, according to thousands of pages of documents related to the case released Wednesday.

The records, about 2,700 pages of police reports, witness statements and other material, detail the events leading up to the attack, from Mr. Loughner’s purchase of ammunition at a Walmart on the morning of the shooting to the response of Pima County Sheriff’s deputies to a bloody Safeway parking lot, where Mr. Loughner had been subdued by bystanders while reloading his 9-millimeter Glock semiautomatic.

The documents, released by the Pima County Sheriff’s Department after Freedom of Information requests from news organizations, reveal the depth of the worries that Mr. Loughner’s parents had about their son’s rapidly deteriorating psychological stability.