Clark County Sheriff Joe Lombardo's briefing comes three days after a lawyer for the police department asked a Nevada state court judge to keep search warrant documents sealed because charges are still being investigated.
A full report is expected toward the end of the year, Lombardo said.
Officer Laura Meltzer, a Las Vegas police spokeswoman, told the New York Post the department is "investigating possible criminal charges related to items discovered during the service of search warrants".
The documents also showed that Paddock's girlfriend, Marilou Danley, told investigators before they searched a house that the two shared that they might find her fingerprints on ammunition "because she occasionally participated in loading magazines", the Las Vegas Review-Journal reported.
Officials with the USA attorney's office and Federal Bureau of Investigation in Las Vegas did not immediately respond to messages seeking comment.
The report mentions Paddock's girlfriend, Marilou Danley, who was out of the country during the attack and who has been interviewed by investigators several times.
Danley, who was in the Philippines during the shooting, was questioned by the Federal Bureau of Investigation after returning to the US. Her lawyer, Matthew Lombard in Los Angeles, did not immediately respond to telephone and email messages Tuesday.
The judge Tuesday didn't order the Vegas police records released as requested by a lawyer for media organizations, including The Associated Press.
Stephen Paddock's remains have been cremated, and his brother Eric Paddock claims that authorities have been making it hard to get access to them. Attorneys now have a week to privately explain their logic to Cadish.
Officials said Paddock was perched on the 32nd floor of a Las Vegas hotel-casino on October 1 when he unleashed a hail of bullets on an outdoor country music festival below as tens of thousands of concertgoers screamed and ran for their lives.