A FAMOUS UFO whistle-blower who claimed he saw top secret Nasa photos showing "alien structures" on the moon has died in a horror bike accident.

Former US Air Force Sergeant Karl Wolfe, 74, was cycling in Lansing, New York, when he was hit by a tractor trailer.

He was rushed to nearby Cayuga Medical Centre but later died from his injuries.

Former US Air Force Sergeant Karl Wolfe, 74, was cycling in Lansing, New York, when he was hit by a tractor trailer.

Former US Air Force Sergeant Karl Wolfe, 74, was cycling in Lansing, New York, when he was hit by a tractor trailer. (Facebook)

CLICK HERE FOR MORE FROM THE SUN

Cops have launched a probe into his death but no charges have been filed against the driver.

'UFO SPOTTED' IN ASIA? BIZARRE LIGHTS SEEN OVER CHINA BAFFLE ONLOOKERS

Wolfe shot to fame in 2001 when he made startling claims that Nasa was covering up evidence of artificial structures on the dark side of the moon.

Sergeant Wolfe had a top secret clearance and worked with the tactical air command at Langley Air Force base in Virginia.

'UFO SPOTTED' OVER MYRTLE BEACH, DISTURBING ONLOOKERS

This story originally appeared in The Sun. For more from The Sun, click here