Police searched the home of the unnamed 28-year-old when his father reported him missing - and found poetry suggesting he planned to kill the guitarist.
The authorities also discovered a letter that the man had signed as Brian May, in which he claimed to be the rocker and suggested the real May was a phoney.
May was advised of the situation, and drafted in 24-hour security to protect his home, according to Britain's Sunday Mirror newspaper.
A police spokesman tells the newspaper, "When officers went into his home they found some quite disturbing material that suggested he wanted to kill Brian May. It was written like a contract to kill (May).
"Although (the man) has no history of violence, we cannot ignore threats like this."
Source: WENN