No evidence deadly gas explosion near Boston was 'nefarious': investigators
Gas company's control centre appeared to have registered pressure increase in area
A federal investigator says there's no evidence to suggest the gas explosions that rocked communities north of Boston were intentional.
National Transportation Safety Board Chairman Robert Sumwalt said Saturday as federal officials opened their investigation into Thursday's disaster that there doesn't appear to be "anything nefarious, anything suspicious, anything intentional."
A series of explosions and fires killed a teenager, injured dozens, damaged homes and forced thousands of people to be displaced.
Sumwalt said it appears Columbia Gas's pipeline control centre in Columbus, Ohio, registered a pressure increase in the Lawrence area.
He said investigators will be working to develop a timeline, including how local utility officials reacted to the pressure increase.
Investigators expect to be on site up to 10 days. A final report could take up to two years.
Watch: Natural gas explosions displace thousands in Boston suburbs