The heirs of the former owners of Belward Farm have filed a lawsuit in Montgomery County Circuit Court asking that Johns Hopkins University be forced to stop plans to develop a 4.7 million-square-foot campus and science park on the property.

The plaintiffs claim that the university has violated the terms of a 1989 agreement that transferred ownership of the farm, northeast of Darnestown and Muddy Branch roads, to Johns Hopkins. They claim the agreement stipulates that the property would be used only for academic purposes, research or medical care with no more than 1.4 million square feet developed.

The new development plan, which calls for a high-rise commercial office park on the former farm, was devised without consultation with the family, family members said.

“Instead of a university-operated campus, Belward Farm would become a university-owned commercial real estate venture whose main goal is not education, university research or medical care, but turning a profit,” Tim Newell of Oldwick, N.J., one of six plaintiffs, said in a statement.

Robin Ferrier, a spokeswoman for Johns Hopkins’ nearby Rockville campus, said the university “does not comment on matters that are in litigation.”

A court date has not been set.

The Belward property is located within the Life Sciences Center, about 900 acres between Gaithersburg and Rockville that were designated in the county’s Great Seneca Science Corridor master plan to become a bioscience hub.

Within the next 30 years, about 17.5 million square feet of commercial space and 9,000 apartments or homes will be developed in the center, bringing thousands of life science jobs.

The family owned the historic Civil War-era farm for more than a century until 1989, when taxes and other costs became too high for the owners to afford, according to a news release from the family. They agreed to sell the land, which they said was thought to be worth as much as $54 million, to Hopkins for $5 million, with the difference representing a charitable donation to the university, the lawsuit filed last week states.

The family agreed to have the property rezoned from residential to research and development, but was dismayed when university officials led efforts to change the plan. In July, the Montgomery County Planning Board approved a preliminary plan amendment allowing Johns Hopkins to map out the larger version on the property. That allows Hopkins to plan for additional development but did not officially give approval from the county beyond the 1.4 million square feet already approved.

“Early in the process, we made known to the university the family’s objections to its current plans,” said Newell, the nephew of the late Elizabeth Banks, the majority owner of the farm in 1989, in his statement. “Instead of working with us to address these concerns, the university has simply maintained that its new plan is not at odds with what my Aunt Elizabeth had in mind. ... It is sad and ironic that John[s] Hopkins, the university my aunt was so fond of, has become the type of developer that she tried so hard to protect the farm from.”

kshay@gazette.net