HOUSTON, Texas -- Police said seven people were shot at an "instant party" at a house in Houston, Texas.According to authorities invitations were sent at random via Snapchat, a messaging app that allows users to exchange pictures and videos that disappear after they're viewed.It's unclear what caused the shooting around 2 a.m. Saturday, but a detective on the scene told our sister station KTRK-TV that it began as a verbal altercation at the party.Authorities said Several people tried to get away from the shooting and took off in a car.The suspect began following them and shot inside their car, striking three people.Police said three additional people were found shot at the home when they arrived.The seventh shooting victim showed up at the hospital.The house party included between 30 to 50 guests and were all teens and young adults, according to police.Police believe there were up to three shooters involved. They described the suspect's vehicle as a tan, newer-model SUV, larger in size.All seven victims suffered non-life-threatening injuries and are expected to survive.People who live in the neighborhood said they heard between 20 and 25 gunshots.Witnesses said a shooting victim showed up at a gas station a few blocks from the scene looking for help.Carlos Ramirez said he heard a young woman crying outside of his home and yelling on the phone. He learned she had been shot in the hand and called her an ambulance."I came outside, and I heard this lady crying and she was yelling on her phone so I peeked and looked and the gunshot was going on. I told her to come inside and wash her hands because you don't know if the people are still out there," he said.The incident remains under investigation.