The incident took place in Greenwich around 3:30 p.m., on Thursday, Nov. 10 on a residential street in the central part of the city.
The USPS mail carrier was approached by two individuals who demanded the property he had on his person, said Lt. Martin O'Reilly, of the Greenwich Police.
"They took items, which we have not released to the public," O'Reilly said. "No weapons were observed."
Police believe the suspects were attempting to obtain the key that opens mailboxes, O'Reilly added.
The investigation is ongoing and the Postal Inspectors Office is involved in the probe, police said.
The mail carrier seems to have been targeted, not personally, but because of his position, O'Reilly said.
There is no known threat to the general public, police said.
Click here to follow Daily Voice Vernon-Rockville and receive free news updates.