The alleged burglary took place in mid-May in the eastern Ohio town of Martins Ferry, and the two allegedly hoped to find photos and other information to sell to a tabloid.
The allegations against Police Chief Barry Carpenter and Bridgeport Police Chief Chad DoJack surfaced about a week later, said the law enforcement official, speaking on condition of anonymity because the investigation continues and no charges have been filed.
The burglars were allegedly after "pictures, phone message, all those things" at the home of the surrogate, Michelle Ross, who is no longer believed to be staying in the area, the official said. Published reports have said she's due to give birth in July.
The official said the allegations are that "two police chiefs were breaking in and trying to sell it to the tabloid," but did not identify the publication.
Martins Ferry Mayor Phil Wallace confirmed the bureau was investigating Carpenter, but wouldn't elaborate.
Parker, the 44-year-old star of the TV show and film "Sex and the City," and Broderick, her 47-year-old husband and fellow actor, have confirmed they're expecting twin daughters by a surrogate because they're unable to conceive since Parker gave birth to a son, who is now 6.
"Matthew and Sarah Jessica have complete faith in the legal system," publicist Simon Halls said in a statement. "But because it's a criminal investigation - we will not be making any more comment. What I can say is the entire family looks forward to the healthy delivery of their daughters later on this summer."
Parker, who lives in New York, said around the time of the break-in that she was concerned for the safety and well-being of the surrogate. She told "Access Hollywood" that she worries about "the safe delivery of our children."
Parker told the television program that the surrogate's telephone and computer had been hacked into, and that she's received threats. She didn't address whether a burglary had taken place.
The law enforcement official said one purpose of the burglary was apparently to ascertain the identity of the surrogate, which wasn't public knowledge at the time of the break-in.
The twin towns of Bridgeport and Martins Ferry lie just across the Ohio River from West Virginia, in a heavily wooded industrial valley and have a total population of about 9,000.
By Joe Mandak