He repeatedly stated that Paddock was the lone shooter in the bloodbath, but said the Federal Bureau of Investigation is still investigating a person of interest in the case.
Child abuse images, snorkel equipment and handwritten notes were among the items found in the hotel room of Las Vegas shooter Stephen Paddock, police have revealed.
Officials have yet to determine a motive behind the shooting that killed 58 people.
Lombardo says the FBI has "an ongoing case against an individual of federal interest".
Paddock's girlfriend, Marilou Danley, told investigators that he had become "distant" in the year before the shooting. "I will not be able to elaborate on that statement".
Some 422 people were injured by gunshots and the total number of injuries associated with the incident was 851, Mr Lombardo said. Investigators also chased 1,965 leads in the case, reviewed more than 21,000 hours of footage and issued 1,062 legal notices.
Lombardo said the investigation found that Paddock had possessed child pornography. He moved from window to window to see the site from different angles, the report said. The shooter's doctor suspected he might have suffered from bipolar disorder and Paddock had told friends he always felt ill, in pain and worn out, according to the Associated Press.
As a gambler known to bet tens of thousands of dollars at a time and play at numerous casinos, Paddock was completely funded by his gambling habits and real estate transactions. The doctor offered him antidepressants, but Paddock accepted only a prescription for anxiety medication.
Police found "several hundred images" of child pornography on the four laptops recovered from Paddock's room, and his "disturbing" search history indicated that he had been looking for the flawless location to conduct his rampage for at least several months. In May 2017, he used the Internet to search "how crowded does Santa Monica Beach get" and "biggest open air concert venues in United States of America", according to the report.
Google search history in an HP laptop showed Paddock researched other large-scale venues, including locations in Boston, Los Angeles and San Diego, the report said.
Searches were also found regarding "SWAT weapons" and police tactics a month before the shooting.
The attorney for the massacre victims, Catherine Lombardo, questioned Perry's information and told him it was "irresponsible" for the congressman to make those allegations without evidence. "Unless you have specific evidence, it seems a bit irresponsible to make that allegation or make that assertion", she said.