Both stations report that unnamed sources told them police investigating the deadly blaze recently searched D&J Ironworks Inc. on Waite Street in Malden.
Authorities have not yet publicly identified the company and declined Wednesday to comment on the news reports naming the business.
Company officials could not be reached for comment Wednesday.
Suffolk County District Attorney spokesman Jake Wark told Boston.com that officials from his office, Boston Police and Boston Fire are reviewing the case and have agreed not to disclose “investigative details’’ until their probe is either further along or complete.
He said the investigation is “still in the fact-gathering stage.’’
The National Institute of Occupational Safety and Health may conduct its own probe, according to spokeswoman Nura Sadeghpour. She said the office’s Fire Fighter Fatality Investigation and Prevention Program is reviewing the incident and expects to determine in the next few days whether it will formally investigate.
The March 26 fire at 298 Beacon St. took the lives of Boston Fire Lieutenant Edward Walsh, 43, and Firefighter Michael Kennedy, 33. Others were injured.
Authorities have said the fire was started by wind-blown sparks made by welders who were contracted to work on an iron handrail next door at 296 Beacon. Officials said they believe the company did not obtain proper city permits for the job.
A spokeswoman for the owners of 296 Beacon also declined Wednesday to identify the company. The property owners have said previously they had thought the welding work was going to be completed offsite.