A 25-year-old Ukrainian man was arrested Saturday in the April 29 death of pensioner Mohammed Saleem.
West Midlands police said in a statement they were questioning the Ukrainian in the explosions in June near mosques in the Black Country of West Midlands.
Forensics specialists are examining an industrial unit in Small Heath where the man was arrested.
Saleem's death "now forms part of the wider West Midlands Counter Terrorism Unit inquiry and will be thoroughly investigated," said Assistant Chief Constable Marcus Beale, who is leading the investigation.
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