Ukrainian student Pavlo Lapshyn packed hundreds of nails into a bomb he planted near a mosque in Tipton.
The device was the most powerful of the three he planted and could exploded only an hour before Ramadan worshippers were set to begin prayers at the mosque.
No one was injured by any of the explosions.
A Ukrainian student has admitted stabbing an 82-year-old Muslim pensioner within five days of arriving in the UK.
Police have released images showing Ukrainian student Pavlo Lapshyn preparing for and carrying out attacks in the Midlands.
A timeline leading up to the conviction of Pavlo Lapshyn, who murdered pensioner Mohammed Saleem and set bombs off outside mosques.