By Katie Marsal

Published: 11:15 PM EST (08:15 PM PST)

Speculation about Steve Jobs' health has reached a fever pitch as at least one eyewitness has claimed Apple's chief executive is back on campus the same day the company itself dropped a possible clue of its own.

An anonymous Reuters journalist on the grounds of the the Cupertino, Calif.-based firm says that Jobs was exiting the building wearing his familiar mock turtleneck and jeans, conversing with an unknown other person and then entering a black car -- not the silver Mercedes SL he's known to often, but not always, drive to work.

While numerous if unverifiable reports have surfaced of Jobs visiting the campus, especially in recent days, the latest instance follows on the same day as Jobs was quoted in a press release for the first time since his leave began in January. Even in the string of high profile product announcements at WWDC, the company's PR dutifully quoted senior VP of worldwide product marketing Phil Schiller, not Jobs -- a likely indicator that Apple views its co-founder as back on the job.

Whether the specific sighting is authentic or otherwise, it would also at least coincide with purported leaks that put Jobs on track for his late June return thanks to a well-timed liver transplant. With the surgery having supposedly taken place two months prior, Jobs would now have had time to recover and take up the reins once again -- albeit in a part-time role at first to avoid placing undue stress on the executive until he's ready to return in earnest.

Not surprisingly, Apple hasn't commented on any sightings and has only maintained that Jobs is due back in late June, which is now at hand.