Researchers are looking at footage showing three glowing lights filmed over Barrie, Ontario, in Canada.
The sighting was reported to the US-based Mutual UFO Network (MUFON), which holds a global database of UFO and alien alleged sightings.
The case has been picked up by UFO blogger Scott C Waring, who runs ufosightingsdaily.com.
He wrote: “This UFO was seen over Ontario last week.
“It does have three lights which could mean its a TR-3B military craft, but its hard to tell at night.
“Sometimes similar UFOs have been reported to suddenly split up and shoot away in opposite directions.
“I wonder if this would have happened if the eyewitness had watched longer?”
The TR-3B is alleged by conspiracy theorists to be a secret “black project” spy craft of the US Government that can be flown into space.
The allegations are that these crafts are created at top-secret military bases like Area 51 in Nevada, by reverse engineering alien technology.
Others claim they are actual UFOs flown by aliens visiting Earth.
In a report to MUFON, the witness, who has not been named, said: “I pulled onto my street heading home and i noticed three bright lights in the sky.
It does have three lights which could mean its a TR-3B military craft, but its hard to tell at night.
“Two were red and one white, flashing very fast.
“I recorded it for a few seconds from my car, until the video went out of focus, then pulled into my driveway and went inside to tell people to come look.
“My brother-in-law came outside and saw it as well.”
The witness said they started recording again and “its white light changed to red and began pulsating slowly with the other two lights now turned off”.
They added: “It then flickered its lights and changed the red pulsating light back to white, continued to pulsate, and then went back to flashing again for the remainder of the time I watched.
“It eventually vanished.”
MUFON is investigating the case.
In the meantime Express.co.uk sent the footage to UFO investigator Scott Brando, who is renowned for exposing hoax and misinterpreted pictures and videos.
He said many reported so-called triangular UFOs turn out to be just aircraft navigation or landing lights.
He said: “The three lights could be related to aircraft, but it’s really hard to identify it as airliner or military aircraft.
“In this case I can only say that those three lights could be related to navigation lights by a plane or a different aircraft.”