ok I found two articles from 1960 (you need to pay to view them i think)
One from NY Times
A Mystery Polar Satellite, Believed Russian, Spotted; POLAR SATELLITE DETECTED BY D. S.
By JOHN W. FINNEYSpecial to The New York Times. (); February 11, 1960
, Section , Page 1, Column , words
WASHINGTON, Feb. 10 -- An unidentified, silent satellite has been discovered circling the earth in a near-polar orbit by United States tracking stations, the Defense Department said today. The identity and origin of the mystery satellite -- which has been dubbed "the dark satellite" are not known despite nearly two weeks of tracking
[link to select.nytimes.com
One a bit later from Time Magazine
Science: Space Watch's First Catch Monday, Mar. 07, 1960But last week the Department of Defense proudly announced that the satellite had been identified. It was a space derelict, the remains of an Air Force Discoverer satellite that had gone astray.
Read more: [link to www.time.com
the whole article is here
[link to furiousfanboys.com
They say it was corona - discoverer V
9002 Discoverer 5 13 Aug 1959
Mission failed. Power supply failure. No recovery.
[link to en.wikipedia.org