One neighbor said the noises sounded like a possible gunfight.
"Sounded like they might be shooting at each other," said a neighbor who declined to be identified. "There is no telling."
Police say the body was found inside a 2015 Camaro with out of state license plates and are investigating who or what agency it belonged to.
"It does have out of state plates," Sgt. Cassandra Lewis, Detroit police said. "But I don't know at this point whether or not it is a rental vehicle."
Residents describe their east side neighborhood on Field Street as normally quiet, saying they were alarmed in the wee hours at the sound of gunshots.
"A big boom, I came out and didn't see anything and went back watching TV," said a neighbor who declined to be identified. "Then I heard some crackling sounds and then a girl ran downstairs and said it's a fire in the alley."
As police search for answers, residents say they're on guard while others plan to be vigilant.
If you have information in the incident, contact Detroit police at (313) 596-5300 or call Crime Stoppers to remain anonymous at 1-800-SPEAK-UP.