PLANO, Texas — Updated 5 p.m. July 21 with information that officials now believe the explosion may have been an intentional act.
Authorities on Tuesday continued to investigate the explosion that leveled a home in Plano and sent six people, including children, to the hospital.
The blast happened about 4 p.m. Monday in the 4400 block of Cleveland Drive in west Plano, destroying the home where it happened and also damaging several nearby homes.
While some details remain limited, we're learning more throughout the day about the explosion.
Here's are the latest updates on what we know (and don't know), so far:
Why did the explosion happen?
Authorities are still in the preliminary stages of their investigation, but Plano Fire Department officials on Tuesday morning said they believe the probable cause of the explosion was an isolated gas leak within the home. Now, officials said they believe the explosion "may have been intentional."
Investigators, though, have not yet determined where the gas leak was inside the home, or how the leak happened. The severe damage to the home was making those investigative efforts difficult on Tuesday.
How many people have been hospitalized?
Six people were hospitalized Monday following the explosion. One victim was inside the home when the explosion happened, and the four other victims - two adults and three children - were residents of the home next door.
The home's resident and two neighboring adults were taken to the nearby Medical City Plano hospital and the three children were taken to Children's Medical Center Plano. The three children have since been released to family members, WFAA learned Tuesday evening.
What are the victims' conditions?
Authorities have not released information about the victims' conditions yet.
The three children are safe with family, had minor cuts, sources told WFAA. The mother and father are still being treated at a nearby hospital.
How was the explosion initially reported?
Plano Fire Department Capt. Peggy Harrell said 911 callers "were using the phrase 'completely gone'" to describe what happened to the home that exploded.
Emergency crews responded and "knew they were arriving to something very, very serious," Harrell said.
When they arrived, neighbors reported that they believed someone was inside the home. The lone resident was extricated from the rubble and taken to a hospital immediately, Harrell said.
How powerful was the explosion?
Harrell told WFAA near the scene that some windows were knocked out on homes across the street from the explosion, and said some residents said they felt the explosion from a mile away, including staff at the Haggard Library.
Doorbell camera video from a neighbor directly across the street caught the moment the explosion happened.
Has foul play been ruled out?
Investigators brought an explosives-sniffing dog to the scene after the incident, but officials said the canine did not detect any explosives or hazardous materials.
However, after initially ruling out foul play, investigators now believe that the explosion may have been intentional. WFAA is working to find out more on what made investigators reverse course.
How long will the investigation take?
Officials can't say how long the investigation will take. The Plano Fire Department is the lead agency investigating the explosion, but the FBI has also assisted in the investigation.
Are any other homes in danger?
Plano officials made this clear: No other homes in the area are in danger, saying the gas leak was isolated solely to the home where the explosion happened.
Are power and gas back on in the neighborhood?
Yes, power and gas were restored Monday night for all homes in the neighborhood, except for the home where the explosion happened and the two neighboring homes, which officials have deemed uninhabitable.