WATCH: Black Helicopter Chases Mysterious UFO

An unsuspected window cleaner was just finishing his cigarette when he spotted a strange object flying across the sky.

According to reports, the strange incident happened on the south of the British coast. As per the video uploaded by the witnessed who was identified as Darren Cooper, the ring-shaped object flew in speed. And as if the UFO was not enough to shock him, Cooper saw a black helicopter trailing behind the UFO.

"As I went back into the house to look at the footage, within two minutes the helicopter was above the house so I ran back outside with the camcorder and the chopper was on the same path as the object in the sky" Cooper said in the video caption.

"Notice in the video the helicopter is turning as if looking for something."

Meanwhile, according to Express, this is not the first time a black helicopter has been seen next to another unidentified object. It was believed that these helicopters have no marking that indicate their identities are part of a covert military force engaged in a secret UFO monitoring program.

Mirror UK reported that according to declassified FBI files, the same black helicopters were spotted during a wave of cattle mutilation cases in Colorado, where animals had organs removed with surgical precision and were completely drained of blood.

A testimony in Case 79232 from the Mutual UFO Network (MUFON) witness reporting database said a witness reported watching a sphere-shaped orb UFO silently moving at the treetop level followed by three black helicopters,.

In an article published in New York Post, journalist Ben Mezrich chronicles Chuck Zukowski's journey as he tries to uncover the truth about the cattle mutilation is Colorado. According to the article cases like these had been happening in many other places for more than a decade. And all of them were unexplained.