A month after we reported on the controversy caused by a mysterious ground-floor business at 4035 18th St., it appears the business has decided to move on. Earlier this week, there was some noticeable work going on inside the space, and a 'For Rent' sign was posted in the window yesterday.

Details on the business were slim, and we were never able to figure out exactly what was going on inside. Thanh Phan, who co-owns the building with Jack Coyne, told us in October that it was an insurance business, but when we visited, a representative declined to comment on the business' name or field. 

A recent change in code requires professional-services businesses operating out of commercial spaces in certain areas of District 8, including the Castro, to seek a conditional use authorization from the Planning Department. After 4035 18th St. received a complaint about illegal use in July, the Planning Department determined that an illegal change-of-use had indeed occurred, and Phan would need to seek a conditional use authorization.

That proved to be too much for the mystery business. "Due to the uncertainty of obtaining conditional use, the business has decided to move on to another location," Coyne told us over the phone. For the moment, they're still seeking a tenant. 

While the space may be vacant, Coyne says he and Phan are still pursuing a conditional use authorization for the space, due to the amount of time they have already invested in the process. We'll keep you updated on what moves in.