A makeshift bomb, or improvised explosive device, detonated Tuesday morning but failed to ignite a gasoline can placed alongside it. No one was injured, but the incident left some shaken in Colorado Springs.
"All of a sudden I heard this big boom," one witness told CNN affiliate KDVR-TV
in Denver. "There was smoke everywhere; the building on the side was burnt."
The witness continued: "Whoever did it took off right away though. That's all I heard and it was scary."
The FBI's Denver office said it's looking for a balding man, about 40, who was seen leaving the scene in a white pickup with a missing or covered license plate.
Another witness, Julie Skufca, told KDVR that she stared at a man as he drove away calmly.
"(It) kind of made your heart stop, especially when you have kids," she told the station.
"He was a heavier white man with what looked like a (Carhartt jacket)" she added. "Just driving normal like it was a normal day."
The FBI has not said if the NAACP was targeted. But some pointed out that the other building tenant, Mr. G's Hair Design Studios, likely was not.
"Who would want to bomb a beauty salon?" one member of the local NAACP chapter told CNN affiliate KCNC-TV
Henry D. Allen Jr., the branch's president, also raised the specter of a targeted attack, telling KCNC, "Apparently, we're doing something correct. Apparently, we have gotten someone's attention that we are working toward civil rights for all. That is making some people uncomfortable."
The NAACP is the nation's oldest civil rights organization. The group's national office says it is looking forward to a "thorough investigation" into the explosion by national and local authorities.
The FBI has asked that anyone with information call its Denver tip line at 303-435-7787.