Executives at a Bay Area company reacted Wednesday to a photograph showing one of their products attached to a device apparently used in the Boston Marathon bombing.
Batteries made by Fremont-based Tenergy Corporation appear in at least two photographs from the scene of the explosions.
The twin bombs at the Boston Marathon killed three people and wounded more than 170 on Monday.
Tenergy says the batteries, called the Sub C-3000, are manufactured in China, and are typically used to power things like remote control cars.
The battery is a widely available retail product, that can be purchased either a pack or as an individual battery from multiple stores in the U.S., as well as on line.
Tenergy said it was not clear whether the battery was purchased individually or as part of a pack.
Tenergy Executive Benjamin Mull said his heart sank when he saw the photos online.
"We were appalled that our product was used in such a horrible and senseless way," Mull said.
Bomb experts tell NBC News the battery pack appears to have been used to ignite whatever blasting cap device was used to set off the explosion.
Tenergy released this statement after executives saw the photos today:
Everyone at Tenergy is deeply saddened by the recent events at the Boston Marathon. Our hearts and thoughts are with the victims and their families. We were appalled to discover that one of our off-the-shelf products was used in such a horrific and senseless act of hate. We have contacted both the FBI and the Boston Police and will assist in any way possible to help identify the responsible parties. Again, our hearts go out to the families and those who were affected by this tragic event in the city of Boston.
Mull said in an interview with NBC that even if FBI officials can identify the model and batch number on the battery pack, it would hard to pinpoint that to a particular store and time.
Tenergy said it has been selling this battery "for several years, it retails for a few dollars, and we have sold tens of thousands of this particular battery over the just the past year."
Scott is on Twitter: @scottbudman