The homemade bomb that blew up a Michigan lawyer's Volvo and injured the man and his two young sons as they headed to football practice may have contained parts from remote-controlled cars, authorities said Thursday as they announced an increase in the reward offered for information.
In raising the reward from $10,000 to $20,000, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) issued a broad appeal for the public's help in locating the suspect or suspects in the Sept. 20 attack on Erik Chappell.
The corporate litigation and family law attorney was taking his sons to football practice in Monroe., Mich., when his car exploded. The vehicle erupted into a fireball and burned down to its metal frame.
The blast was so strong that it was heard a mile away.
"It was mayhem with inside the car," Chappell told ABC News. "We were all dazed. I noticed flames on my side and the passenger side."
Chappell, who practices law mainly in Michigan and Ohio, sustained injuries to his right arm. His sons, who were 10- and 13-years-old, were seriously wounded.
The three have since made a full recovery. Chappell has said that he believes he knows who tried to kill him, but has declined to make that information public.
"It would have required some proximity in order to detonate it," he said. "They would have had to know that the boys were in the car."
Police say the bomb was placed to inflict as much damage as possible.
The device contained shrapnel - meant to increase its lethality, ATF Special Agent in Charge David McCain said in a statement.
"It is disgusting that the suspect was willing to kill innocent children to achieve his or her goal," McCain stated.
The bomb was homemade but contained commercial components from toy vehicles, including possibly from those manufactured under the brand names Electric RC, Ruckus Monster Truck (Orange), Ruckus Monster Truck (Green), Circuit Stadium Truck (Red), Circuit Stadium Truck (Gray), Boost Buggy (Orange) and Boost Buggy (Blue).
The suspect would have knowledge of electronics, radio control circuitry, tools and metal-working. The suspect also would have had a private work space to store, assemble and construct the device, McCain said.
Members of the public may unknowingly have information about the suspect. He asked anyone who may recognize the skills and traits described as belonging to someone they know to come forward.
"If you have direct knowledge of this case and fear for your safety, we can protect you," he added.
The ATF is asking anyone with information to call 1-888-ATF-BOMB (1-888-283-2662) or ATF ANN ARBOR at 1-734-887-0060.
"It's fairly disconcerting that as a result of doing your job you would end up in a situation that we've been in over the past six months," said Chappell.