PORTLAND, Maine (AP) — Federal authorities are investigating the crash of a twin-engine cargo plane near a small airport in central Maine that killed both people on board.

The Beechcraft crashed in a field in the town of Litchfield at around 5:45 p.m. Tuesday, the Federal Aviation Administration said. The agency said the National Transportation Safety Board would lead the investigation.

The plane crashed “under unknown circumstances” about half a mile (0.8 kilometers) from Wales Airport, said Sarah Taylor Sulick, a spokesperson for the NTSB. Authorities had not identified the two dead as of Wednesday.

Litchfield is a small town close to the state capital of Augusta, and is about 50 miles (80 kilometers) north of Portland, the largest city in Maine.

“The investigator will document the accident site, airplane, and gather witness statements and any surveillance video that may have captured any part of the accident flight,” Taylor Sulick said.

Wreckage from the crash will be recovered and moved offsite for analysis, Taylor Sulick said, adding that a preliminary report about the crash will likely be available in two to three weeks.

The plane took off Tuesday from Lewiston airport, about 18 miles (29 kilometers) from Litchfield, according to the aircraft tracking website FlightAware. The plane is owned by Wiggins Airways of Manchester, New Hampshire, records state.

Wiggins Airways’ website states that the company is an all-cargo airline with operations in 12 states. It also states that the company “provides time critical feeder services for major express carriers, namely FedEx and UPS.” A representative for the company declined to comment Wednesday on the crash.

The primary local investigating authority on the crash is the Kennebec County Sheriff’s Office, said Shannon Moss, a spokesperson for the Maine State Police. Moss said Maine State Police is assisting with the investigation and declined to comment further.

This scene is very large and it will take two to three days to attend to it, said Kennebec County Sheriff Ken Mason in a Facebook post.

“As we continue our work on the incident in Litchfield, please be patient with our response time for non-emergency calls for service through out the county,” Mason said. “Please keep the families of the two souls lost in your thoughts.”