Indiana authorities have made an apparent break in their investigation into who triggered the massive explosion that killed two people and leveled some of an Indianapolis neighborhood earlier this month.
"Our investigators are talking to individuals we have identified as potentially having relevant information," Prosecutor Terry Curry said.
Earlier this week ABC News learned that authorities are now saying they believe the blast in the subdivision just south of Indianapolis Nov. 10 that killed John and Jennifer Longworth was caused intentionally.
Police won't say who they are questioning, but cell phone video captured by Brad Horton and his girlfriend Whitney Essex shows a SWAT team descending on a mobile home park in southwest Indianapolis.
"These people came in tanks with people on top of them," Essex told ABC News.
The couple says their neighbor Bob Leonard was led away for questioning. Leonard is the brother of Mark Leonard, who is dating Montserrate Shirley, who along with Mark Leonard, lives in the home that exploded.
"It was pretty serious. They don't pull those [tanks] out for just anything," Horton said.
Much of the attention since the explosion has centered on Shirley and Leonard, who lived at the house in the center of the blast area. The two ignored questions from reporters on Tuesday.
The couple says they were at a casino, and the home was empty when the explosion rocked the quiet neighborhood, killing the Longworths and damaging nearly 100 homes.
An attorney for Shirley and Leonard said they are cooperating with police.
Overnight, prosecutors refused to confirm if they believe Bob Leonard is involved, or if they believe the blast was triggered by remote.
"As we develop additional information, and identify individuals who potentially have pertinent information, we'll just pursue all those leads and that's exactly what we're doing," Curry said.
John Shirley, who owns that house but now lives elsewhere, told ABC News two days after the blast that he believed that his ex-wife, who still lives in the house, was to blame for the explosion.
Shirley claimed he knew that the furnace in the house was broken and had not been fixed properly, if at all.
"If I were to suspect anything, that's where the problem was," said Shirley, who noted that his ex-wife Monserrate Shirley had a "protective order" against him.
Shirley said he did not believe his ex-wife would have caused the explosion intentionally.
"I don't think so, because there was no real reason to," Shirley said. "I pay a thousand dollars a month for one kid because she had a lawyer and I did not, so she has more than enough money. At one point the house was slipping into foreclosure. Last spring she had a buyer but she chose not to sell. We were in some bankruptcy but that's pretty well cleared up."