Six people died after an explosion in a house in Athens old town Plaka, and police have now arrested three men suspected of causing the blast. More than a month after the incident, investigators say surveillance footage shows the suspects approaching the building around 2.00 a.m. on the night in question, about five and a half hours before the explosion. The men are accused of entering the building’s stairwell and leaving a few minutes later with a piece of copper pipe. Investigators believe they damaged the building’s underground gas line while trying to remove it. Authorities say the escaping gas then collected inside. When a reportedly old light switch was used in the morning, that ignition triggered the explosion. The blast collapsed the house and also damaged nearby buildings, according to ERTNews. The Greek foreign ministry said two married couples from the United States were among the six victims, along with a British man and a Greek woman. The three suspects are in custody as the investigation continues.