A construction crew found a mummified body in the wall of a convention center in Oakland, California, on Wednesday, authorities said.
A worker found the body around 1 p.m. in a wall that was being deconstructed during renovations at the Henry J. Kaiser Convention Center, according to the Alameda County Sheriff's Office.
"We found remains best described as mummified," Lt. Ray Kelly told NBC News. "The conditions in the walls were such that the body was preserved in good conditions."
Authorities said the mummified body was in late stages of decay and had likely been there for "several years."
"Any theory is possible," Kelly added, according to NBC News. "It could be anything from someone who got in behind the wall and became trapped and died to someone put the person there. God only knows."
The decomposition of the body made it impossible to immediately determine the person's age or gender, the sheriff's office said.
Authorities are conducting further forensic testing, Oakland Police Department spokesperson Kim Armstead told the Mercury News.
The convention center first opened in 1915 but has been closed since 2005, the paper reported.
However, in 2015, the City Council reached an agreement with a developer to lease the building and turn it into a commercial and performing arts space.
The Associated Press contributed to this report