A string of attacks on European IKEA stores have left company officials and police baffled. The latest scare occurred in the German city Kiel on Wednesday, just five days after the minor explosion of an incendiary device at one of the Swedish retailer's stores in Dresden. For most IKEA shoppers, the largest concern is whether they will be able to assemble their new sleeper-couch once they get it home. Recently, though, shoppers at some outlets of the Swedish furniture giant have begun to worry about their safety.

Customers in Germany have been left shaken by a recent bomb attack at an IKEA warehouse store in Dresden and an additional scare on Wednesday in Kiel. The incidents came on the heels of a string of attacks in late May on outlets in neighboring Belgium, France and the Netherlands. Ongoing investigations have made little headway. On Wednesday evening, officials at an IKEA in the northern port city Kiel discovered a suspicious "mobile device" and quickly cleared out the store. Ultimately, a bomb squad brought didn't find any explosive devices, but the incident does underscore how nerves have been rattled by the Dresden attack.

IKEA says it has no information on the background of the Dresden attack, which occurred last Friday. The earlier attacks likewise remain a mystery. A company spokeswoman said earlier this week she would not speculate on any possible motives behind the attack. The company did say, however, that it has not received any threats.

Looking for a Connection

The explosion in the Dresden store happened in the kitchen department at around 7:45 p.m. on Friday evening. The damage to IKEA property was limited, but two customers were slightly injured -- with a 32-year-old woman and a 41-year-old man both suffering acoustic trauma. The store was cleared out and a special police unit, complete with five bomb-sniffing dogs, inspected the premises. By Saturday, the store had reopened to the public.

The Dresden explosion is similar to those which took place on May 31 at IKEA branches in Ghent, Belgium, the French city of Lomme and the Dutch city of Eindhoven. Investigators with the the Saxony State Criminal Police Office (LKA) said this week they haven't ruled out a connection between the Dresden incident and the others. Authorities do believe, however, that the late May explosions are linked, but have yet to pinpoint a connection.

On Tuesday, police in the Netherlands released security camera footage of a man suspected of involvement in the Eindhoven attack. The footage shows a man walking towards the IKEA furniture store but not entering. Shortly after, a small explosion went off in a trash can outside the store. Police officials in Germany said they are in contact with their Dutch counterparts about the case and expect to receive copies of the footage in the near future.

New Leads in Dresden

On Wednesday, German authorities revealed that several e-mail messages claiming responsibility for the attack in Dresden had been received. LKA officials are in the process of analyzing the messages, the content of which is largely similar.

"We are investigating intensively to figure out who was behind this," an LKA spokeswoman told reporters on Wednesday. Police said they are trying to determine whether the person or people behind the letters were actually responsible for the explosion. They did not say, however, if any demands had been made or whether threats of further attacks had been made.

German news agency DAPD reported Wednesday that messages claiming responsibility for the attack were sent to both the LKA in Dresden and IKEA, but neither organization would reveal details about their contents.

Hoever, Dresden's Dresdner Neuesten Nachrichten newspaper reported what it claimed to be the contents of the letter in its Thursday issue. "With this letter, I claim responsibility for the attack on IKEA Dresden," the letter-writer reportedly stated. The newspaper claimed that the sender had written the letter in broken German and had demanded an eight-digit sum of money and claimed the person would commit further attacks of the money hadn't been received within seven days. The e-mail, sent from a Yahoo address, the paper reported, also included a photo of a young man. But sources told the newspaper it could also have been sent by a copycat.

Increased Vigilance at IKEA Stores

So far, neither witnesses nor surveillance video from the IKEA store has turned up any promising leads for investigators in the case, and police have been unable to identify any suspect. Police have created a composite sketch of what they believe the Dresden suspect may look like, which was broadcast on a popular German crime-solving show on Wednesday night. But a spokeswoman for KLA said one day later that only about 10 leads had been generated by the show and that none had brought the investigation forward.

In response to the attack, IKEA officials said Wednesday they had increased security measures. "Security standards at IKEA are very high at all of our furniture stores," the company. "One measure will be that we will place uniformed security guards in front of our stores. That is a purely preventative measure to protect our employees and customers."

Earlier this week, IKEA Germany spokeswoman Sabine Nold said employees at the company had been asked to increase their alertness and vigilence and had been trained to detect possible threat situations. Spiegel International

With reporting by Alison Kilian, Hendrik Ternieden and Jens Witte