KITTERY – Like the inmates who once tried to escape from its concrete towers, developers trying to transform a former naval prison into an upscale office complex aren’t getting very far.

Developer Joseph Sawtelle of New Castle, N.H., was the man behind the $12 million renovation project. Work stopped about a month after his death in May and has yet to resume.

“There’s nothing going on,” said Tim Sheldon, director of development for Seavey Island LLC, the company established by Sawtelle to rebuild the prison into the Seavey Island Technology Center. “We’re in the same position as we were before.”

The prison’s original stockade was built in 1898 to house Spanish-American War prisoners. The building was renovated in 1908 to jail court-martialed U.S. military personnel and was modeled after Alcatraz prison in San Francisco Bay. The northern wing, added in 1942, gave it a more pronounced “castle” look, and the southern wing, known as the “Fortress,” was added a year later. The maximum-security brig was closed in 1974.

Under Sawtelle’s plan, the Fortress wing would have been reopened last summer. Instead, it remains vacant while Seavey Island LLC tries to lease or sell the project to another party. The company holds a lease with Naval Sea Systems Command that allows it to sublease the building.

Redevelopment of the prison is vital to the shipyard’s efforts to increase efficiency by consolidating the work force, removing outdated, unnecessary buildings and making underused facilities available to private companies.

Capt. Vernon Williams, shipyard commander, said such projects would help protect against future rounds of base closures.

“Leasing underutilized facilities helps achieve the affordability part of the equation by reducing the costs of maintaining the shipyard’s infrastructure,” Williams said.

Developers hoped to attract large national and international technology companies to the site, which they planned to turn into 270,000 square feet of commercial space with room for up to 1,000 employees.

Many of those companies, however, have been hit by the slowing economy. Ross Gittell, an associate professor of management at the University of New Hampshire, said the seacoast could see a dip in demand for large office spaces.

“We would not anticipate big declines in employment, but on the other hand, we’re not going to be experiencing the same growth rates that we’ve seen in the last five years,” he said.

However, Gittell said what drew people and jobs to the seacoast during the boom will head off a potential bust. The attractiveness of Portsmouth’s downtown, the area’s skilled work force and proximity to Boston, plus the relatively cheaper cost of space will remain assets, he said.

Those factors bode well for Sawtelle’s dream eventually becoming a reality, he said.

“In the short term, it might not look as promising of an investment,” Gittell said. “But long term there isn’t an oversupply of office space here, and we’re well positioned, so there would be opportunity to successfully fill that space, in say, two years from now as the national economy recovers.”