"We X-rayed the bag and were able to determine it was nothing more than clothing and some screws and some nails, no sort of fuel or accelerant or anything in the bag," Crosier said.
A short time later staff members at the Charleston Treatment Center, a methadone clinic, called 911 after receiving a call that someone had placed an explosive device in their Dumpster.
The bomb squad left the downtown scene and headed to the clinic.
"We responded with some officers to begin evacuations and make the area safe before we sent in our bomb technicians," Crosier said.
The bomb squad issued an all-clear call at the Marriott about noon and a second all-clear at the methadone clinic about 1 p.m.
The Tuesday incidents were at least the second and third in the city since the April 15 Boston Marathon bombings.
On April 17 a suspicious backpack was found at the Sacred Heart Pavilion at the corner of Leon Sullivan Way and Quarrier Street in downtown Charleston. It was later determined not to be a threat.
The Boston bombings involved devices fashioned from pressure cookers holding ball bearings and other shrapnel. They were placed in backpacks and dropped near the finish line.
While the tragedy illustrates that each threat needs to be thoroughly investigated, officers always have responded to such situations in a similar fashion, Kanawha County Sheriff John Rutherford said.
"It's the public's reaction that's changed over the last few days," Rutherford said. "A few months ago, a backpack with nails and screws in it probably wouldn't have been reported."
It's rare for the area to experience three bomb threats in one week, he said.
Investigators are trying to determine if the threats are connected. No suspects have been named.
State Police offered assistance with the Charleston Treatment Center call.
Although the situation downtown turned out to be a false alarm, Rutherford praised the hotel workers for reporting the backpack.