A proposed grocery store at Diagonal Plaza has moved closer to coming to fruition.

The identity of the mystery tenant; however, has not.

The individuals behind a nearly 52,000-square-foot grocery store at 3303 30th St. earlier this month resubmitted portions of the building permits to respond to Boulder planning staff members' comments and questions.

Such a move is a typical next step in the permitting process as the new documents, filed Jan. 3, included tweaks in areas such as landscaping and electrical to address planning officials' feedback.

Little more was revealed about the store's operator.

During the past year, speculation has swelled that the space's tenant is Walmart Inc., which has recently expanded its Neighborhood Market grocery store concept throughout Colorado.

Other signs emerged that seemed to increase the likelihood that Walmart could be the mystery tenant behind the grocery store at Diagonal Plaza.

Although the initial minor modification and building permit documents filed last summer with the city contained little identifiable information about the tenant, items such as a store number, certain paint and shelving materials and the design of the cart corrals bear remarkable similarities to other Walmart Neighborhood Market stores in the region.

Additionally, a slew of companies that operate grocery stores inside and outside the region have not laid claim to the project.

The 3303 30th St. project's architecture firm, property owner and Walmart have not returned multiple inquiries seeking comment. City officials and council members have said they have not had any direct communication with the tenant.

City planning officials are reviewing the latest submission and are scheduled to deliver any additional comments, if necessary, by this week, said Mike Banuelos, a city spokesman.

In recent months, initial construction work concluded at the proposed grocer's site. The property owner previously received approval to modify the site by combining the long-vacant former PetSmart and Ross stores into one contiguous space.

The construction and proposed tenant finish related to the new grocer mark the first significant development activity and movement at Diagonal Plaza in years. City officials have targeted the shopping center off 28th Street and Iris Avenue as ripe for redevelopment.

Boulder Mayor Matt Appelbaum said city officials still don't know whether the proposed store is, in fact, a Walmart, though it is widely assumed that it is.

Even if the application were more transparent, City Council members generally don't see applications unless they involve land-use changes or other significant decisions.

"We don't care about the tenant," he said. "We care about things like parking."

If a developer or building owner is following city regulations, there isn't much the City Council can or should do to stop it.

However, some City Council members raised concerns about larger retail operations that don't offer good pay and benefits at the council's retreat Saturday.

Councilwoman Lisa Morzel suggested the city look at the broader social impacts of such stores in the future, though any discussion of that issue likely wouldn't occur until 2014 and wouldn't affect current plans.

Camera Staff Writer Erica Meltzer contributed to this report.

Contact Camera Staff Writer Alicia Wallace at 303-473-1332 or wallacea@dailycamera.com.