Two Eastern European men have been arrested in connection with the explosion near Aisha Mosque in Walsall last month.
The 25-year-old and 22-year-old were arrested just before 3pm today.
Police are searching an area of Talbot Way in Small Heath and as a precaution homes have been evacuated.
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David Brickwood was killed at his home last year in what police believe was a pre-planned robbery.
Merlin, the operator of the park, has been told it should expect a "very large fine" for breaching health and safety.
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