The plane struck a utility pole and crashed around 4:00 pm Tuesday, bursting into flames.
The National Transportation Safety Board said Wednesday that the crash of a small aircraft in East Hartford, Connecticut on Tuesday appears to be "the result of an intentional act."
It's now handing over the investigation to the FBI.
The plane came down near Pratt and Whitney, which makes military and commercial jet engines.
Authorities said a student pilot and an instructor were trying to land a Piper PA-34 Seneca at Brainard Airport in Hartford when it struck a utility pole and crashed around 4:00 pm Tuesday. It burst into flames.
One passenger was presumed dead, while a second was hospitalized and treated for burns, and is expected to survive.
Police said there were two sets of controls aboard the small plane, but it was unclear who was controlling the plane when it crashed.
East Hartford Mayor Marcia Leclerc told The Associated Press that the survivor told local detectives the crash was not an accident. But Leclerc cautioned that the information has not been confirmed. At a news conference Wednesday morning, officials did not comment on the reports.
Earlier, four federal law enforcement officials told The New York Times similar information.
The pilot, who survived the crash, told investigators that it was not an accident. The officials spoke on the condition of anonymity because the investigation was continuing.
BREAKING: Several agencies responding to a plane crash on Main St. in East Hartford. #wfsb
— Sujata Wycoff (@SujataTV) October 11, 2016
(Photo from Nancy Blackmer) pic.twitter.com/UR1megsTrM
The Hartford Courant reported that the apartment of the student on Annawan Street in Hartford was searched late Tuesday night.
Watch video from the moments following the crash on Tuesday:
Connecticut Governor Dannel Malloy told reporters he was briefed on the crash. He said it's tempting to jump to conclusions, but he urged people to be patient as facts are sorted.
"As a nation, we have all had to adjust to a new reality," Malloy said. "When events such as this occur, we recognize that people almost automatically wonder if someone meant to do us harm. But we must exercise caution about jumping to conclusions, before discovering and considering all of the facts. The fact is that the plane did crash in one of our neighborhoods, and of course that's reason enough to be concerned."
Heather Brandon contributed to this report, which includes information from The Associated Press.