Two men have been arrested by Copenhagen Police in the investigation of a failed bomb attempt in Valby last month.

“We have arrested two Polish men aged 37 and 53,” the deputy police commissioner, Thomas Dürr, wrote in a press release. “They have been living in Denmark for a while as they have been both working as entrepreneurs.”

The family discovered a canister of petrol connected to a battery with wires in their garage on August 14. Several nearby houses had to be evacuated after the police were called in to defuse the bomb.

After the incident, the family said they had no enemies but they did admit to having had a dispute with a labourer. The incident is being treated as attempted murder.

The 37-year-old was arrested on September 13 and was remanded in custody for four weeks. The 53-year-old was arrested on Saturday and police can keep him in custody until Tuesday.

“We have performed searches at different addresses in Zealand during our investigation and have found a lot of material of interest,” Dürr wrote, adding that they have determined a motive. “The investigation indicates that the bomb was intended to be used for extortion but, because the trial has been held behind closed doors, we cannot provide more information.”