Law enforcement sources, cited by ABC News, said the device also contained details on the criminal investigation into Hillary Clinton’s use of a private email server.
CBS News, also quoting police sources, said the laptop held important files on Pope Francis, too.
And the Daily News says the agent has told investigators that some information on the device has the potential to compromise US national security.
“There’s data on there that’s highly sensitive,” a police source told the newspaper. “They’re scrambling like mad.”
Authorities have been searching for the laptop since it was stolen on Thursday morning from the agent’s vehicle near her house in Brooklyn, New York, the New York Daily News reported.
The US Secret Service confirmed one of its employee’s laptops had been stolen, and said its agency-issued laptops contain multiple layers of security and are not permitted to hold classified information.
Some items reportedly taken at the same time as the laptop – including coins and a black bag with the Secret Service insignia on it – have since been recovered.
The agency said it would not comment further while an investigation takes place.