Police received several reports of loud bangs shortly before 10PM on Tuesday evening. Nobody seems to have been injured in the attack that may have been caused by fireworks being set off against the front door.
Forensic scientists and the army bomb squad attended the scene. Federal judicial police are investigating the incident and will probe any possible link to drug rings operating in the northern port city.
In recent months several similar attacks have been attributed to the settling of accounts by drug traffickers.