BOSTON (Reuters) - Authorities briefly evacuated homes on Sunday after discovering what appeared to be bomb-making materials, firearms and ammunition in a dead man's home in Lawrence, Massachusetts.

Residents of the six homes in Lawrence, about 30 miles (48 km) north of Boston, and neighboring Methuen were allowed to return after about three hours once investigators determined there was no threat, said John McInnis, deputy fire chief in Lawrence.

Authorities learned about the firearms and suspicious materials from the deceased man's mother. She called police after finding them while cleaning out his apartment, McInnis said.

He said that investigators were testing chemicals found in the scene to determine their composition. The three-story apartment building where the materials were found is on the border between Methuen and Lawrence.

Officials with the Lawrence Police Department and Massachusetts State Police declined comment on the status of the investigation.

(Reporting by Jim Finkle; Editing by Ian Simpson and Eric Walsh)

Massachusetts residents evacuated after weapons , bomb-making materials discovered in dead man's home