The reason why a pipe bomb had exploded at a branch of mega-cheap supermarket Lidl in western Germany in April had remained a mystery for weeks, reports Der Westen.

But on Tuesday, the district court in Bochum issued arrest warrants for two suspects in connection with the attack.

The charge against the married couple from nearby Gelsenkirchen is that they attempted to extort supermarket chain Lidl for millions of euros and were prepared to kill to get what they wanted.

The pipe bomb was a step in this drastic scheme, Bochum prosecutors allege.

It exploded on April 15th in a bin at a recycling station at the Lidl branch in Herten, North Rhine-Westphalia, lightly injuring a female employee, who was struck by shrapnel.

According to Der Westen, Rüdiger D. (48) and Liana D. (54), dreamed of owning a house in Spain. But they didn't plan on doing it in the time-honoured way – after a life time of mundane work, two years before you kick the bucket.

They had set a deadline of September to leave their dilapidated apartment in Gelsenkirchen and head for pastures new, planning to use the money extorted from Lidl.

Now though, they face a murder charge as prosecutors are convinced they would have stopped at nothing to achieve their dream.

Investigators claim that they detonated the bomb remotely, via a mobile phone, and could not see the bin in which they had thrown it – for all they knew, someone could have been right next to it when the bomb went off.

A not-so-speedy getaway

Three days after the bomb attack, Lidl received an email saying that if they did not hand over €1 million euros within a month, more explosions would follow. Not only that, but if the discounter did not pay up within this time frame the ransom would be doubled to €2 million.

But the method this slapstick Bonny and Clyde chose to receive the ransom made the audacious plan all the more implausible.

They registered three credit cards under false identities. But each of the cards had a daily withdrawal limit of €320 euros on it, meaning it would have taken slightly under three years to withdraw all their loot.

Keeping in mind that Lidl has made its name by being as cheap as is conceivably possible, they also didn’t demand the whole sum upfront. The supermarket was to pay €3,000 into each of the three accounts every month.

For the discount chain, this was a price they were prepared to pay to catch their blackmailers.

But, while they paid in the initial ransom, state police started investigating who the criminals behind the plot could be.

It didn’t take long before the trail was warm and undercover cops started filming the pair on their daily trips to the bank.

An array of different disguises, including wigs and face masks, was unable to save them. After the couple had withdrawn €1,200, investigators decided to move in and arrested them.

If a court finds the couple guilty they face a minimum of five years in jail each.