The list of dubious dealings involving scandal-plagued German President Christian Wulff just keeps getting longer. But public prosecutors are hampered from investigating the allegations because of Wulff's immunity as head of state. Now they are considering the nuclear option: asking parliament to revoke his protection. This article was written by Spiegel journalists whose names are listed at the end of this article.

Nowadays, being seen as a friend of the German president can be awkward, exhausting and even dangerous. David Groenewold, 38, a film producer, networker and party animal, was truly a close friend of President Christian Wulff for a number of years. Acquaintances of the Berlin-based businessman say that he sat down a few weeks ago and wrote out a list of incidents that could prove to be uncomfortable for him or Wulff.

There are 12 items on the list. For Groenewold, the most worrisome incident appeared to be the short vacation he spent with Wulff and his wife on the island of Sylt from Oct. 31 to Nov. 3, 2007, because he had no receipts as documentation. All he remembered was that he had paid for the Wulffs' suite in the Hotel Stadt Hamburg with his credit card, at €258 ($343) a night. Groenewold called the hotel to ask for a copy of the bill, but the staff was uncooperative at first.

Groenewold drove to Sylt to resolve the matter. The hotel's executive secretary gave him the copies, at which point he jokingly asked, in front of two other employees, whether it might not be possible to tear the page documenting Wulff's visit out of the guest register. Everyone had a good laugh, says Groenewold's acquaintance.

Last week, a different version of Groenewold's intervention on the island of Sylt appeared in the German tabloid Bild. According to the hotel records, the film producer called the hotel on Jan. 16 and requested that it release "no information" about him and the fact that he had paid the Wulff's hotel bill to curious members of the media. A to-do list addressed to staff members includes the following instruction: "So if Bild or Spiegel calls, we don't know anything!" When Bild asked Wulff's attorney who paid for the vacation, he replied: "Mr. Wulff reimbursed Mr. Groenewold for the disbursed costs of his stay on the premises of the Hotel Stadt Hamburg." The payment was allegedly made in cash.