Emilio Lopez, right of CBD Construction, sprays mud from the front sidewalk. African-American human remains that are believed to be pre-Civil War were discovered on September 10th in the 3000 block of Q St. NW while construction was taking place in the rear of the home. (Sarah L. Voisin/WASHINGTON POST)

When the metal claw of a Bobcat tractor crashed into a human skull during a home improvement project in Georgetown last month, all work stopped. D.C. police were called, then the medical examiner.

But shortly after officials analyzed the remains, found in an octagonal wooden coffin with rusted nails that was four to five feet below ground, it became clear that this was no crime scene. The dead simply had started to rise in Georgetown — again.

For the second time in seven years, human remains have been unearthed in the 3300 block of Q Street NW. In 2005, masonry workers removing part of a Q Street rowhouse’s brick foundation found a jaw, some ribs and several joints. Experts later determined that they had been there at least 100 years, most likely placed in a grave lost to history.

This time around, five sets of remains have turned up. On Sept. 10, workers repaving a driveway and building a garage discovered two sets of human remains after hitting a skull. On Sept. 20, two more skulls, along with another set of remains, were discovered by construction workers in the back yard of the home and an excavation began.

“We were lying on our bellies, just using our arms to excavate the burial,” said Ruth Trocolli, an archaeologist with the District’s Historic Preservation Office. She, David Hunt, a forensic anthropologist from the Smithsonian, and her team — including one staffer, two volunteers and her husband, a retired archaeologist — spent 48 hours working to remove the remains.

More remains found from former cemetery near Volta Park.

“I definitely underestimated the amount of time,” she said of their weekend’s worth of work.

Trocolli and Hunt, who are called in when it’s clear that remains have been someplace awhile and the circumstances do not appear to be suspicious, said it is likely that more remains will be found — and not just in Georgetown.

With tractors revving up and businesses and homeowners once again looking to build or renovate, they said there’s no telling what — or who — might turn up. That’s why Trocolli is working to create a database of the discoveries. She hopes to make a comprehensive list of where the bodies are buried.

There are lots of historic burial sites in the District, some that the city knows about and others whose whereabouts have been misplaced, Trocolli said. Over the past few years, she and her team have been using a geographic information system, which stores, edits and analyzes data to show trends or patterns. The system allows Trocolli and her team to create an interactive mapping system of known burial sites.

Many of the first burial sites logged into the database came from Washington cemetery historian Paul E. Sluby Sr.’s book “Bury Me Deep: Burial Places Past and Present in and Nearby Washington, D.C.” Sluby’s book is an alphabetical guide to some of Washington’s oldest burial sites and is considered by experts as the most extensive archive of this information.

Sometimes the work can be tedious, Trocolli said, like attempting to put together the scattered parts of a 100-piece puzzle. Burial records are not kept in a uniform database. Churches that have cemeteries on their land often keep records of burial plots, but over time that information can become hard to find.

“Georgetown was a free-standing town. The records could be in Maryland,” Trocolli said of the recently discovered remains. “There’s lost, and there’s, ‘We haven’t looked yet.’ ”

There’s also the added challenge of determining when and how remains are excavated from construction sites: Legally, the medical examiner must be called first when remains are found in case a crime has occurred. In the past, that has often led to researchers like Trocolli not being notified when a possible historic burial site was discovered.

Now, Trocolli said, she and the chief medical examiner are trying to collaborate more to improve the record-keeping and preservation of the remains.

A familiar discovery

The discovery of remains has become all too familiar to residents along Q Street. The homes sit across from Volta Park, the site of a former Presbyterian cemetery established before the American Revolution.

At it’s height, the cemetery was a final resting place for several of Georgetown’s most important residents, including a few of its mayors, and contained nearly 2,700 graves. By the start of the 20th century, however, the once prominent burial site fell into disrepair and became mostly abandoned. In 1907, the land was converted to use for a playground and swimming pool. Later, it became the park, leaving some unmarked graves behind, according to historical records.

In 2005, the remains of a teenager between the ages of 12 and 15 and of African descent, were found just a few houses down from the recent discovery, Hunt said. A discarded tombstone was found on the roof of a home in 1957, and a skull turned up near the foundation of another home a year later. And in the early 20th century, longtime Georgetown resident Eva Eden’s father discovered nine sets of skeletal remains while working to enlarge the family’s basement.

Hunt said it is difficult to determine exactly how long any of the remains may have been there. But those found in recent years are under homes built in the mid- to late 1800s.

Last week after discovering remains, Hunt visited the office of the medical examiner to get a second look at the five sets of body parts. He said he thinks all are of African descent because of the structure of the mandibles.

The first two sets of remains discovered were found near the corner of the home and along the east wall of the construction area and are thought to be from two males, one mature and the other in his mid-20s or early 30s at the time of death, Hunt said.

The three sets of remains discovered a little more than a week later included two young adult females and one male. All were found near the back yard of the home.

The numbers

Hard numbers about just how many remains have been unearthed as a result of construction in the District are difficult to come by because each office working with the data uses the information for different purposes. The medical examiner uses it to identify the deceased and possible cause of death, and the Historic Preservation Office uses the information to alert contractors using federal money for development projects.

At the moment, all parties seem to be intrigued about remains.

“I’m interested if there will be more burials on that square,” Trocolli said. “As a homeowner, if you want to build an addition to your home, what you’re really concerned about is will you find more human remains?”