HOUSTON --Local and federal investigators were at a northwest Houston home Friday night where an explosion sent a woman to the hospital. The woman was opening a package left at her doorstep in the 2100 block of Seamist Court Friday evening. She had found the shoe-sized box in front of her home about a day ago but didn't decide to open it until around 6:30pm Friday. The woman, who officials said is in her 60s, took the box to the backyard and opened it on the patio. That's when it exploded. "Don't know where it came from -- postal service or whether it was dropped off. I don't have that information yet," said HPD Lt. Colin Weatherly."The person went outside, basically opened the packaged; it detonated." Residents told Eyewitness News that when the bomb went off, it sounded like a transformer blew. The woman was transported to Northwest Memorial Hospital with facial injuries that are not life-threatening. Officials with the Alcohol, Tobacco and Firearms, as well as the Houston Police Department's homicide and bomb squad were at the scene investigating. It wasn't immediately clear whether the house was targeted, however, Eyewitness News found out the home is owned by an oil company executive. Stay with Eyewitness News for updates to this story.