In the back of the house at 753 Walnut St. in Camden, back through a small gravel alley that glitters with broken glass, over piles of debris and under a crumbling roof, you can just make out the boarded-up window of a bedroom that may have been where the Rev. Dr. Martin Luther King Jr. stayed in 1950, when he was a student at the now-closed Crozer Theological Seminary in Upland.

King was living at the house when he was refused service at a bar in nearby Maple Shade, an incident that sparked his lifelong crusade for civil rights, according to activist Patrick Duff, who has compiled dozens of documents on the time period.

But Duff is confronting an unexpected challenge in his lengthy effort to get the site, vacant for years, marked for historic preservation: Last month, the City of Camden issued a demolition notice to the property's owner, Jeanette Lily Hunt.

The notice, dated July 8, came more than a year and a half after Duff first applied for the historical designation, which would protect the building from being razed and make it eligible for thousands of dollars in historical preservation grants.

Camden Urban Enterprise Zone program coordinator Vincent Basara said last week the city does not plan to demolish the house, but issued the notice as part of a routine maintenance effort. The city only wants Hunt to bring the property into compliance with codes intended to minimize urban blight, he said.

Still, Hunt and Duff fear that the house will be demolished and Hunt will be slapped with the bill for it.

That's what happened, she said, when the city made a debris-management demand earlier this summer: Before the deadline she had for cleaning up the property, she said, the city cleaned the area and sent her a bill for $515.74.

With a place on the historic registry secured, Duff, 40, said he would hope to turn the house and the adjacent vacant lot into a historical site commemorating King's Camden legacy. Still, although the Maple Shade incident is well-documented, the length of time King spent in the Camden house has been disputed, and that could be yet another hurdle to gaining the historical designation.

Hunt, now 85, remembers King's days in the house, then owned by her father-in-law. King would have been in his early 20s.

He was "part of the family," she said - "just a nice man, very nice." Hunt said restoring the house as a historical site would be "an exciting and important thing."

But more than a year after the application was submitted in January 2015, Duff and Hunt are still waiting to hear from the state's historic preservation office.

A spokeswoman said last week that the application is still under review. In May 2015, a spokeswoman told the Inquirer that the office expected to finish its work "within the next two weeks." She said last week that the timeline was unclear as the agency had requested additional information.

Duff said the state is dragging its feet because of questions about how much time King spent in the house. He insisted that the substantial evidence he has already presented should be sufficient.

Benjamin Hunt, Jeanette Lily Hunt's father-in-law and the owner of the house during King's time, told the Courier-Post in January 1981 that King had lived there "on and off for two years," a recollection Hunt shares.

But David Garrow, a historian and the author of the King biography Bearing the Cross, said he believes King spent time in Camden and likely only occasionally stayed at the Walnut Street house, where he visited his friend Walter McCall, Benjamin Hunt's cousin. But Garrow said he does not believe King lived there for any significant stretch of time, based on interviews with Crozer classmates and other evidence.