A 19th-century boy whose body was found in a cast-iron casket in April at a Columbia Heights construction site probably died of pneumonia, a team of scientists has determined. They said they believe his family was wealthy.

The body is that of a 13- or 14-year-old boy who died in the mid-1800s, said Michele Urie, a spokeswoman for the Smithsonian Institution's National Museum of Natural History, where the team is working.

Because the casket was tightly sealed, the level of preservation is "extraordinary," Urie said. "To find one is rare," she said of the casket. "To find one that has been sealed and airtight is very rare."

Led by forensic anthropologist Doug Owsley, the group doing the analysis includes pathologists, anthropologists and a clothing expert. Archaeologists and D.C. historians will try to determine the boy's identity, Urie said. They will also research whether the location where the body was found is a former cemetery site. It is possible that the boy's grave was accidentally left behind when a cemetery was moved.

Urie said the pants, shirt, vest and socks the boy was buried in are characteristic of 19th-century fashion. The use of cast iron for the casket indicates that the boy's family was wealthy; cast iron was expensive, especially after the start of the Civil War, when it was in heavy demand, she said.

The scientists plan toxicological and pathological screens that could reveal evidence of other diseases, medicine the boy may have taken and his general health.

"It's a great insight into what life in Washington, D.C., was like in the 1850s," Urie said.

The casket was unearthed at 1465 Columbia Rd. NW by a construction crew. The discovery soon drew crowds, prompting workers to lock the casket in an empty building. That night, vandals broke in, cracked the casket's faceplate and broke the glass below.

The Smithsonian took possession of the casket the next week, but only now has a team of scientists had the opportunity to fully analyze the remains, Urie said.