Jack Healy has this article in The New York Times:

Utah Court Strips Criminal of Right to Counsel, and Some Lawyers Object

For David M. Corbett, a lawyer in Salt Lake City, the breaking point came when his client, a white supremacist convicted of murdering a prison officer, began threatening him, then managed to learn Mr. Corbett’s home address and mailed him an envelope of legal papers. Mr. Corbett, rattled, asked to be taken off the case.

The Utah Supreme Court agreed, but it went a big step further in an unusual ruling that added an asterisk to one of the bedrock rights of America’s legal system. The court said that the defendant, Curtis Allgier, had behaved so badly with so many court-appointed lawyers that he had forfeited his right to counsel as he appealed his murder conviction.

“Forfeiture is a drastic measure,” the court wrote in a ruling.  But it said that in this case, it was justified in cutting off his access to public defenders: “Mr. Allgier has made a series of threats to multiple appointed appellate attorneys.”

You can access the per curiam ruling of the Supreme Court of Utah at this link.