A suspicious letter was found in Maastricht on Wednesday, after two mail bombs exploded in Amsterdam and Kerkrade earlier in the day. There was no explosion in Maastricht, the Limburg police said on Twitter. Minister Sander Dekker for Legal Protection called the blasts "worrying". "As far as we can see now, there are no victims, no injuries. So that's great," he said to De Limburger. "For the rest, the police must investigate."

The third suspicious package was found late Wednesday morning at an ABN Amro location in the Limburg city, according to NOS. "It is obviously a hot item at the moment, given Amsterdam and Kerkrade. If there is a report, we take it very seriously."

Later in the afternoon, police said that the suspicious package was an envelope containing a computer mouse. There was no further cause for alarm at the bank branch.

The national coordinator for counter-terrorism and security NCTV said it is keeping a close eye on the situation around the mail bombs, but for the time being the investigation is in the police's hands.

The explosion in Amsterdam happened at an ABN Amro national mail sorting center on Bolstoen just before 8:00 a.m. "An employee of the mail sorting center wanted to open the letter and heard a hissing sound," the police said in a statement. "The employee threw the letter away, after which there was a slight bang." 

The bang was comparable to that of a firecracker, a police spokesperson said to NOS. "But if you have it in your hands and it goes of, it can cause serious injury," the spokesperson said. According to the police, the employee responded exactly right and came away with nothing more than a fright.

The building was evacuated while the Ministry of Defense's explosive clearance department EOD searched for any further explosives. Nothing was found. 

"I think it's terrible," ABN Amro CEO Kees van Dijkhuizen said while presenting the bank's quarterly figures, according to NOS. "Of course you sometimes read it in newspapers, but if it happens to you, it scares you even more." He said he has no idea where the letter could have come from. No warning letter was received either, he said.

Half an hour after the explosion in Amsterdam, a postal package exploded at company Ricoh in Kerkrade. According to De Limburger, Ricoh specializes in digitizing mail. According to the police, an employee heard a noise from the package, followed by a bang. Nine people were in the room at the time. No further explosives were found in the building.

"We are very upset," a spokesperson for the company said to NOS. "We are in close contact with our employees to be able to offer them the right support. Fortunately, there were no injuries, but the people involved were of course very shaken."

A neighboring company took in the Ricoh staff. "We saw the police and fire brigade and then we knew enough," an employee of that company said to the broadcaster. "The neighbors came by and are now with us. The were shocked."

Late in December and early January, mail bombs were delivered to seven companies in Amsterdam, Rotterdam and Utrecht. None of those bombs exploded. All of them were followed by threatening letters. An ABN Amro branch in Maastricht received a letter, but no bomb. The mail bombs were made to look like they came from CIB - a central collection agency in Rotterdam.. The police assume there was one person or group behind the mail bombs.

The Amsterdam police are leading the investigation into all mail bombs because most of the bombs were found in the capital, a spokesperson said to RTL Nieuws. "We are working closely with other criminal investigation departments in the country," he said. "Whether there is a connection between the mail bombs in Amsterdam and Kerkrade and whether it is a single sender, investigation must show." So far they police have "no link" to the perpetrator, the spokesperson added. "We also have no idea of the motive behind the bomb letters. Today's explosions give the investigation a new boost."