AUSTIN, Texas (AP) — Police in Texas are investigating an explosion that killed a man early Friday on his front porch as an isolated homicide.

Austin police, postal inspectors, FBI and U.S. Bureau of Alcohol, Tobacco and Firearms agents were helping determine what kind of device caused the explosion just before 7 a.m. Friday. Police have not identified the man who died at a hospital from injuries related to the blast.

Austin Police Chief Brian Manley says police do not believe the incident is related to terrorism. He says his agency are working with postal inspectors to determine whether a package was delivered to the home recently.

Neighbors reported hearing the explosion and seeing the bloodied man collapse on his porch.