The circumstances behind the shooting were unusual. Homicide Sgt Mark Holbrook said there was a small party.
"The victim put on a bullet proof vest and another man who has a gun winds up shooting him," he said. "It's unusual, but these things happen sometimes."
Mary Warstler wasn't at the party, but she's the longtime girlfriend of the man police are talking to.
"He went there to sell his friend a flak jacket," she said she was told by her boyfriend. "It's so bad because he didn't know the gun was loaded." She identifies her boyfriend as 39-year-old Jason Griffin.
She said he told her that he went to sell his friend the bulletproof vest. According to what she said Griffin told her, "he even asked, 'Brother, do you want me to cinch that up for you,' but they were playing this stupid game going around."
"He said 'shoot me,' and he [Griffin] didn't think there was anything in it, and he did," Warstler said. "He tried to take the vest off and save him."
Police said he left the scene. Warstler said he returned to Rosenberg early this morning, shaken and afraid.
"He felt bad for what happened to his friend," she said. Later, he returned to Houston, she said to meet with police, but had two seizures and was taken to Ben Taub Hospital.
According to an HPD news release, the suspect was taken into custody without incident Sunday afternoon after being treated at a hospital for a medical issue. The case will be referred to the district attorney's office to determine what charge may be filed.
RELATED: Man shot and killed at party after putting on bulletproof vest
Man killed after putting on bulletproof vest