First US PB: Zebra (1987)
-pictured below

Synopsis:

Shades Of Death

It had to be the specter of the long-dead Cavalier Sir Byng Rawdon who ghosted into the Oak Room at Telford Old Hall one night, spirited the bejeweled Cavalier's Cup from the locked safe... and left it standing on a table nearby. The room's windows had been firmly latched, the heavy doors double-bolted from the inside- and a live witness had spent the entire night there and seen nothing!

Enter Sir Henry Merrivale

But the famous detective Sir Henry Merrivale wasn't spooked by ghost stories - in fact, impossible crimes always put him in high spirits. A very live intruder was haunting the Hall, and it was up to the redoubtable Sir Henry to unmask the ubiquitous bugbear before his deviltries materialized into a more murderous form of mischief!