wreckage say, luckily, it appears no one was killed. david, investigators tonight now working to figure out what exactly caused that explosion. david? alex, thank you. and next, the shocking image of an arrest in galveston, texas, tonight, sparking outrage. it shows the suspect being walked through the street, a rope linking his handcuffs to two officers mounted on horses. the police chief is now apologizing tonight, saying the officers showed poor judgment. here s steve osunsami. reporter: this is the disturbing photo that s all over the internet that galveston police are trying to explain tonight. the picture was taken saturday as police on horseback were arresting 43-year-old donald neely. his family says he has a history of mental illness and lives on the streets. i can t even imagine what they were thinking to say, we re going to use this today. reporter: now, there s video, too. he is, indeed, being led down the middle of a texas street by a rope, and the many critics t